Does discourse able to collaboratively work on a document and maintain revisions and I have following doubts

  1. Can the user create the Group? is it any other way to do it ?
  2. is it possible to create the subgroup under group?
  3. Group administrators to have authority to Approve/reject group

Yes, you can create wiki posts.

Groups can be created only by admins (maybe moderators?), which solves the problem of admins approving groups. :slight_smile:

There are no sub-groups. You would need to create the “sub-group” and manually add the members of the group to the sub-group.