Mi Doc Viewer
cn.wps.xiaomi.abroad.lite
Allows users to view various types of documents on their Android devices like documents (*.doc/docx, *.ppt/pptx, *.xls/xlsx, *.pdf, *.wps, and *.txt) and it’s powered by WPS Office
FYI: WPS is a Chinese closed-source software. It’s as bad as Microsoft Office (privacy-wise)