This service uses LibreOffice and Unoconv for file conversion.

Supported file types should include the below however for a full updated list of supported formats, please refer to the LibreOffice documentation

Microsoft Word: (DOC, DOCX, DOT, DOTX)

Microsoft Excel: (CSV, XLS, XLSX, XLT, XLTX, SLK, DIF)

Microsoft PowerPoint: (PPT, PPTX)

OpenDocument Formats: (ODT, OTT, ODS, OTS, ODP, OTP, ODG, OTG)

Plain Text: (TXT, TEXT, XML)

Rich Text Format: (RTF)

Images: (BMP, GIF, JPEG, PNG, TIF, PBM, PGM, PPM, RAS, XBM, XPM, SVG, SVM, WMF)

HTML: (HTML)

Lotus Word Pro: (LWP)

StarOffice: (SDA, SDC, SDD, SDW, STC, STD, STI, STW, SXD, SXG, SXI, SXW)

Other: (DBF, FODS, VSD, VOR, VOR3, VOR4, UOP, PCT, PS, PDF)

https://help.libreoffice.org/latest/en-US/text/shared/guide/supported_formats.html