How do I sort or move DONE items in org-mode?
I'm kind of new to org-mode in Emacs, and I'm investigating if it is suitable to replace Google Tasks for me. Google Tasks offers a "clear completed tasks" action, that removes all tasks that are marked done. Can I do something similar in org-mode with DONE items?
Yes, in org-mode you do archive DONE tasks (within the same file or to a subling file). You can use C-c C-x C-a for that.
Please refer the manual Capture, Refile, Archive