A TMDX file is a document created by TextMaker, a word processing application included with SoftMaker Office. It may contain text, images, drawn objects, and page formatting properties. TMDX files replaced TMD files, which were used to store documents by previous versions of TextMaker.

TMDX file open in SoftMaker Office TextMaker 2018 TMDX files are saved in a proprietary format and are the main file type associated with TextMaker, which is similar to Microsoft Word. TMDX files are used similarly to how .DOC and .DOCX files are used by Microsoft Word. A TMDX file is created to store a spreadsheet and can be closed and reopened for further editing. TMDX files may be created from a .TMV and TMVX templates or DOC and DOCX documents. They may also be converted to various formats in TextMaker, including .PDF, DOC, DOCX, .DOTX, .TMD, TMV, TMVX, .ODT, .PSW, and .RTF.