I want to open Word, Excel, Power Point and PDF files on Android. However, I searched for an app for that, but I don’t know. So please tell me about the app. What you need is open source. (However, other than LibreOffice. I tried the app, but it didn’t work. Development is not progressing.)
I’m not aware of any open source app able to do that, apart from Libre Office (but it’s only a viewer, and experimental). If you take this requirement out, then yes.
Word for Android to begin with (for Word docs), or SoftMaker Office HD Basic for Android : free, with word processor, spreadsheet, presentations and database.
PDFs are easy. There are a ton of apps able to open them.
OnlyOffice and MuPDF.
(I use Libre Office and it works for me). For PDF files I use Secure PDF Viewer (made by Daniel Micay)
I use muPDF, and have tried Libreoffice viewer, only office, softmaker office, officesuite (from mobisystems)… And IMHO, if you need office app on your phone, use MS products. None of those mentioned above is good in terms of privacy, but at least MS products are good and least annoying. When I need it, I install Excel, and remove it when I don’t need it anymore