Files do not open on mobile devices

This app is complicated to use. Wants files to be moved to their folder rather than open from cloud service directly. Also wants you to download MS office even though I already had it on my iPad. I wanted to copy and paste from a PDF and edit was a one time trial feature. Also demands a link w FB or Google but Google or email sign-in didnt work. Looks like contacts or advertising is wanted. Dont waste your time w this app.

Nurse Teacher9801 about Polaris Office - PDF & Docs, v7.3.9