LibreOffice works for 99.99% of the cases where Microsoft Office is being used. Moreover, NextCloud offers a free "LibreOffice on the web" capability if you prefer.
Oh, BTW. Nextcloud is also nice. Very nice.
Edit: Looks like Owncloud guys have arrived (just joking, I like them equally).
I got access to a NextCloud instance as part of my Hetzner storage.
Setting up access for my wife was easy. Adding "apps" to my nextcloud instance was easy. Sharing storage, playing with a Kanban board, editing documents, it all just works.
I'm very impressed with nextcloud, I had no idea it was so good!
Oh, BTW. Nextcloud is also nice. Very nice.
Edit: Looks like Owncloud guys have arrived (just joking, I like them equally).