How to read documents in RTF file type? I'm searching a way to maintain RTF files for open/editing but at least for reading, because I have no support for it on my device.

I tried mobile docs view and yozo office but they didn't support RTF.
To read RTF files you basically just need and app that supports that file format.

Here's a good one that additionally supports many other document types:

Cool Reader by Vadim Lopatin available from Google Play Store.


  Reading books in epub, fb2, txt, doc, rtf, html, chm, tcr, pdb, pml formats.
  
  eBook reader. Supports epub (non-DRM), fb2, doc, txt, rtf, html, chm, tcr, pdb, prc, mobi (non-DRM), pml formats.