RTF is one of the most common text formats that has a long history. After all, it was developed back in 1982 at Microsoft. The name of the format is an abbreviation of the English Rich Text Format File. Compared to DOC, this is a more universal format that can be used by almost any, even the simplest, text editors. Another of its features is the ability to transfer text between different programs, if the operating system provides the function of export / import of RTF files. Users also appreciate RTF for the fact that such a document can only contain text, without additional heavy macros.
PPTX is a more modern and convenient presentation format in the popular Power Point application, which replaced PPT after entering the Microsoft PowerPoint 2007 market in updated office suites. Full name - Microsoft PowerPoint Open XML Document. Designed for the same purposes as PPT - creating a presentation in an editable slide show format. The difference from the first version is that the PPTX file is created using the open XML format. If in the PPT format the data is stored in one binary file, then in the PPTX format - in a compressed ZIP archive as a collection of separate files.