Yep. Admins can appoint and remove mods for communities that are based on their instances.
If you're interested in taking over a non moderated community on Blahaj Lemmy, send me the details and I'll see what we can do
There's no formal process, but basically, I'll need to be able to see that you're active in the sub in question, that you've got an existing good faith and inclusive posting history, and that the moderator is genuinely inactive. If they haven't posted recently, I'll DM them and give them 48 hours to reply