the basic type of formats used in onlyoffice document editors is ooxml (docx, xlsx, pptx). other types of supported formats (odt, doc, rtf, epub, mht, html, htm, ods, xls, csv, odp, ppt, dotx, xltx, potx, ott, ots, otp, and pdf-a) are processed with inner conversion to docx, xlsx or pptx.