[GTALUG] What app/platform to share/edit document?

Hi all, What app or platform do you or your company use to share/edit document for a group of people?  Main use would be to put all internal documentation, comment, discovery, and faq into one location. * People say "SharePoint", but never used it myself. * We (old job) use to put Word documents on server.  Only one person could write to it at a time, but that was okay for the low traffic. * Plain HTML file might be okay.  Edit by Notepad++.