I wonder how is the compatibility of LibreOffice version for Android if I can open a document in *. Doc or *. Docx and save it in what format I want, if the opposite is also possible. If yes, if it works “perfectly” or have their shortcomings.
There is no version for Android, and compatibilities with Microsoft Office have been answered multiple times on this Q&A website. To view OpenDocument files (that e.g. LibreOffice produces by default), see Is there an LibreOffice ODF viewer for Android?