The text file format is used to store data either in plain text or something more structured depending on the program that has created it or is going to use it.
text format files
| File Extension | Format type |
| 1ST | Readme File |
| 602 | Text602 Document |
| _DOC | Renamed Microsoft Word Document |
| _DOCX | Renamed Microsoft Word Document |
| ABW | AbiWord Document |
| ACT | FoxPro Documenting Wizard Action Diagram |
| ADOC | AsciiDoc Document |
| AIM | AIMMS ASCII Model File |
| ANS | ANSI Text File |
| APPODEAL | Appodeal Text File |
| APT | Almost Plain Text File |
| ASC | Autodesk ASCII Export File |
| ASC | ASCII Text File plain text human-readable plain text, usually no more specific |
| ASCII | ASCII Text File |
| AsciiDoc | an open human-readable markup document format semantically equivalent to DocBook |
| ASE | Autodesk ASCII Scene Export File |
| ATY | Association Type Placeholder |
| AWP | Ability Write Template |
| AWT | AbiWord Template |
| AWW | Ability Write Document |
| B | Brainf*ck Source Code File |
| BAD | Exchange Badmail File |
| BBS | Bulletin Board System Text |
| BDP | Exchange Diagnostic Message |
| BDR | Exchange Non-Delivery Report Body File |
| BEAN | Bean Rich Text Document |
| BF | Brainf*ck Source Code File |
| BIB | Bibliography Document |
| BIB | BibTeX Bibliography Database |
| BIBTEX | BibTeX Bibliography Database |
| BML | Braille 2000 Braille File |
| BNA | Barna Word Processor Document |
| BOC | EasyWord Big Document |
| BRX | Beam Report Document |
| BTD | Business-in-a-Box Document |
| BTXT | BTXTPad Document |
| BWD | BanglaWord Document |
| BXT | Balabolka Text Document |
| BZABW | Compressed AbiWord Document |
| CALCA | Calca Document |
| CAST | Asciicast Terminal Recording |
| CEC | Studio C Alpha Upgrade File |
| CHARSET | Character Set |
| CHORD | Song Chords File |
| CNF | configuration file substantially software-specific |
| CONF | configuration file substantially software-specific |
| CFG | configuration file substantially software-specific |
| CNM | NoteMap Outline File |
| COD | Atlantis Word Processor Encrypted Document |
| COPF | Copy Operation File |
| CRWL | Windows Crawl File |
| CSS | cascading style sheets |
| CSV | comma-separated values |
| CWS | Claris Works Template |
| CYI | Clustify Input File |
| DCA | DisplayWrite Document |
| DEL | Delimited ASCII File |
| DESCRIPTION | youtube-dl Video Description |
| DFTI | FlexiWrite Document |
| DGS | Dagesh Pro Document |
| DIFF | ext file differences created by the program diff |
| DIZ | Description in Zip File |
| DM | BYOND Dream Maker Code |
| DNE | Netica Text File |
| DOC | Microsoft Word Document |
| DOCM | Microsoft Word Macro-enabled Document |
| DOCX | Microsoft Word Document |
| DOCXML | Microsoft Word XML Document |
| DOCZ | ThinkFree Online Note Document |
| DOTM | Microsoft Word Macro-Enabled Document Template |
| DOTX | Microsoft Word Template |
| DOX | MultiMate Document |
| DROPBOX | Dropbox Shared Folder Tracker |
| DSC | Text Description File |
| DVI | Device Independent Format File |
| DWD | DavkaWriter File |
| DX | DEC WPS Plus File |
| DXB | Duxbury Braille File |
| DXP | Duxbury Print File |
| EBP | Express Burn Project |
| EIO | Yozo Office File |
| EIT | Yozo Office Template File |
| EMBED | Embed Notes Note |
| EMF | Jasspa MicroEmacs Macro File |
| EML | E-Mail Message |
| EMLX | Apple Mail Message |
| EMULECOLLECTION | eMule Data File |
| EPP | EditPad Pro Project |
| ERR | Error Log File |
| ERR | FoxPro Compilation Error |
| ETF | ENIGMA Transportable File |
| ETX | Structure Enhanced Text (Setext) File |
| EUC | Extended Unix Code File |
| FADEINTEMPLATE | Fade In Template |
| FAQ | Frequently Asked Questions Document |
| FBL | CADfix Command Level Log File |
| FCF | Final Draft Converter File |
| FDF | Acrobat Forms Data Format |
| FDR | Final Draft Document |
| FDS | Final Draft Secure Copy |
| FDT | Final Draft 5-7 Template |
| FDX | Final Draft Document |
| FDXT | Final Draft 8 Template |
| FFT | Final Form Text File |
| FGS | Fig Figure Settings File |
| FLR | Flare Decompiled ActionScript File |
| FODT | OpenDocument Flat XML Document |
| FOUNTAIN | Fountain Script File |
| FPT | FoxPro Table Memo |
| FRT | FoxPro Report Memo |
| FWDN | fWriter Document |
| GDOC | Google Docs Shortcut |
| GFORM | Google Forms Shortcut |
| GJAM | Google Jamboard Shortcut |
| GMAP | Google My Maps Shortcut |
| GMD | GroupMail Message |
| GPD | Generic Printer Description File |
| GPN | GlidePlan Map Document |
| GSCRIPT | Google Apps Script Shortcut |
| GSD | General Station Description File |
| GSITE | Google Sites Shortcut |
| GSLIDES | Google Slides Shortcut |
| GTABLE | Google Fusion Table Shortcut |
| GTHR | Gather Log File |
| GV | Graphviz DOT File |
| HBK | Mathcad Handbook File |
| HHT | Help and Support Center HHT File |
| HIGHLAND | Highland Document |
| HS | Java HelpSet File |
| HTML | hyper text markup language |
| HWP | Hanword Document |
| HWP | Hangul Text Document |
| HZ | Chinese (Hanzi) Text |
| IDX | Outlook Express Mailbox Index File |
| IIL | CleanSweep Installation Log |
| INI | a configuration text file whose format is substantially similar between applications |
| IPF | OS/2 Help File |
| IPSPOT | iPhoto Spot File |
| IPYNB | Jupyter Notebook |
| JARVIS | Jarvis Subscriber File |
| JIS | Japanese Industry Standard Text |
| JNP | Java Web Start File |
| JOE | JOE Document |
| JP1 | Japanese (Romaji) Text File |
| JRTF | JAmes OS Rich Text File |
| JSON | JavaScript Object Notation is an openly used data format now used by many languages, not just JavaScript |
| JTD | JustSystems Ichitaro Document |
| KES | Kurzweil 3000 Document |
| KLG | KOFIA Log |
| KLG | Log File |
| KNT | KeyNote Note File |
| KON | Yahoo! Widget XML File |
| KWD | KWord Document |
| LATEX | LaTeX Document |
| LBT | FoxPro Label Memo |
| LICENSE | Software License File |
| LIS | SQR Output File |
| LNK42 | Windows 93 Desktop Shortcut |
| LNT | Laego Note Taker File |
| LOG | Log File logfiles usually text, but sometimes binary |
| LP2 | iLEAP Word Processing Document |
| LST | Data List |
| LST | FoxPro Documenting Wizard List |
| LTR | Letter File |
| LTX | LaTeX Document |
| LTXD | Light Text Editor Document |
| LUE | Norton LiveUpdate Log File |
| LUF | Lipikar Uniform Format File |
| LWP | Lotus Word Pro Document |
| LXFML | LEGO Digital Designer XML File |
| LYT | TurboTax Install Log File |
| LYX | LyX Document |
| MAN | Unix Manual |
| MBOX | Email Mailbox |
| MCW | MacWrite II Document |
| MD | MuseData Musical Score, Markdown an open lightweight markup language to create simple but rich text, often used to format README files |
| MD5TXT | Message Digest 5 Hash File |
| ME | Readme Text File |
| MELL | Mellel Word Processing File |
| MELLEL | Mellel Document |
| MELTEM | Mellel Template |
| MIN | Mint Source File |
| MNT | FoxPro Menu Memo |
| MPD | MPEG-DASH Media Presentation Description |
| MSG | Outlook Message Item File |
| MSS | CartoCSS Map Stylesheet |
| MW | MacWrite Text Document |
| MWD | Mariner Write Document |
| MWP | Lotus Word Pro SmartMaster File |
| NB | Nota Bene File |
| NDOC | Naver Word |
| NFO | Warez Information File |
| NGLOSS | Nisus Writer Glossary |
| NJX | NJStar Document |
| NOTE | Notability Note File |
| NOTES | Memento Notes File |
| NOW | Readme File |
| NWCTXT | NoteWorthy Composer Text File |
| NWM | Nisus Macro |
| NWP | Now Contact WP Document |
| OCR | FAXGrapper Fax Text File |
| ODIF | Open Document Interchange Format |
| ODM | OpenDocument Master Document |
| ODO | Online Operating System Write Document |
| ODP | Organ Definition Project |
| ODT | OpenDocument Text Document |
| OFL | Ots File List |
| OMFL | Open Multiple Files File List |
| OPEICO | Opeico Text File |
| OPENBSD | OpenBSD Readme File |
| ORG | Emacs Org Text Document |
| ORT | Rich Text Editor Document |
| OTT | OpenDocument Document Template |
| P7S | Digitally Signed Email Message |
| PAGES | Apple Pages Document |
| PAGES-TEF | Pages iCloud Document |
| PDPCMD | Pdplayer Command File |
| PFX | First Choice Word Processing Document |
| PIMX | Adobe Package Installation Management File |
| PLAIN | Plain Text File |
| PLANTUML | PlantUML File |
| PMO | Pegasus Saved Message File |
| PRT | Printer Output File |
| PRT | Crypt Edit Protected Text Format File |
| PSW | Pocket Word Document |
| PTNX | EasyBeadPatterns Pattern |
| PU | PlantUML File |
| PVJ | ProofVision Job Ticket |
| PVM | Photo Video Manifest File |
| PWD | Pocket Word Document |
| PWDP | Password Pad Document |
| PWDPL | Password Pad Lite Document |
| PWI | Pocket Word Document |
| PWR | PowerWrite Document |
| QBL | QuickBooks License File |
| QDL | QDL Program |
| QPF | QuickPad Encrypted Document |
| QUID | QuidProQuo Document |
| RAD | Radar ViewPoint Radar Data |
| README | Readme File |
| RFT | Revisable Form Text Document |
| RIS | Research Information Systems Citation File |
| RPT | Generic Report |
| RST | reStructuredText File |
| RTD | RagTime Document |
| RTF | Rich Text Format File |
| RTFD | Rich Text Format Directory File |
| RTX | Rich Text Document |
| RUN | Runscanner Scan File |
| RVF | RichView Format File |
| RZK | File Crypt Password File |
| RZN | Red Zion Notes File |
| SAF | SafeText File |
| SAFETEXT | SafeText File |
| SAM | LMHOSTS Sample File |
| SAM | Ami Pro Document |
| SAVE | Nano Temporary Save File |
| SCC | Scenarist Closed Caption File |
| SCM | Schema File |
| SCRIV | Scrivener Document |
| SCRIVX | Scrivener XML Document |
| SCT | FoxPro Form Memo |
| SCW | Movie Magic Screenwriter Document |
| SDM | StarOffice Mail Message |
| SDOC | Satra Khmer Document |
| SDW | StarOffice Writer Text Document |
| SE | Shuttle Document |
| SESSION | Mozilla Firefox Session File |
| SGM | SGML File |
| SHIM | Scoop Shim File |
| SKCARD | Starfish Sidekick Card File |
| SLA | Scribus Document |
| SLAGZ | Scribus Compressed Document |
| SMF | StarMath Formula File |
| SMS | Exported SMS Text Message |
| STORY | Storyist Document |
| STRINGS | Text Strings File |
| STW | StarOffice Document Template |
| STY | LaTeX Style |
| SUBLIME-PROJECT | Sublime Text Project File |
| SUBLIME-WORKSPACE | Sublime Text Workspace File |
| SW3 | Scriptware Screenplay |
| SXG | Apache OpenOffice Master Document |
| SXW | StarOffice Writer Document |
| TAB | Tab Separated Data File |
| TDF | Guide Text Definition File |
| TDF | Xserve Test Definition File |
| TEMPLATE | Apple Pages Template |
| TEX | LaTeX Source Document |
| TEXT | Plain Text File |
| TEXTCLIPPING | Mac OS X Text Clipping File |
| TFRPROJ | theFrame Project File |
| TID | TiddlyWiki Tiddler |
| TLB | VAX Text Library |
| TM | TeXmacs Document |
| TMD | TextMaker Document |
| TMDX | TextMaker Document |
| TMV | TextMaker Template |
| TMVX | TextMaker Document Template |
| TPC | Topic Connection Placeholder |
| TRELBY | Trelby File |
| TSV | tab-separated values |
| TVJ | TrueView Job Ticket |
| TXT | Plain Text File |
| U3I | U3 Application Information File |
| UNAUTH | SiteMinder Unauthorized Message File |
| UNX | Unix Text File |
| UOF | Uniform Office Document |
| UOT | Uniform Office Document |
| UPD | Program Update Information |
| UTF8 | Unicode UTF8-Encoded Text Document |
| UTXT | Unicode Text File |
| VCF | Variant Call Format File |
| VCT | Visual Class Library Memo |
| VNT | Mobile Phone vNote File |
| VPDOC | VoodooPad Document |
| VW | Volkswriter Text File |
| VWR | Velconoe Write Document |
| WBK | WordPerfect Workbook |
| WEBDOC | Boxnet Web Document |
| WN | WriteNow Text Document |
| WP | WordPerfect Document |
| WP4 | WordPerfect 4 Document |
| WP5 | WordPerfect 5 Document |
| WP6 | WordPerfect 6 Document |
| WP7 | WordPerfect 7 Document |
| WPA | ACT! Word Processing Document |
| WPD | WordPerfect Document |
| WPD | 602Text Word Processing Document |
| WPD | ACT! 2 Word Processing Document |
| WPL | DEC WPS Plus Text Document |
| WPS | Microsoft Works Word Processor Document |
| WPS | Kingsoft Writer Document |
| WPT | WordPerfect Template |
| WPT | Kingsoft Writer Template |
| WPW | WP Works Word Processor File |
| WRI | Microsoft Write Document |
| WSD | WordStar Document |
| WTT | Write! Document |
| WTX | Text Document |
| XBDOC | Xiosis Scribe Document |
| XBPLATE | Xiosis Scribe Template |
| XDL | Oracle Expert Definition Language File |
| XDL | XML Schema File |
| XML | an open data format |
| XWP | XMLwriter Project |
| XWP | Xerox Writer Text Document |
| XWP | Crosstalk Session File |
| XY | XYWrite Document |
| XY3 | XYWrite III Document |
| XYP | XYWrite Plus Document |
| XYW | XYWrite for Windows Document |
| YAML | an open data format |
| ZABW | Compressed AbiWord Document File |
| ZRTF | Nisus Compressed Rich Text File |
| ZW | Chinese Text File |
| ZZQ | Zyzzyva Quiz |
| ZZS | Zyzzyva Search |