By default users not logged in do not have any editing permissions. By default brand new logged in users also do not have any editing permissions but can more freely navigate the wiki without risking being flagged as bots or alike.
There are a lot of system-managed User Groups that you do not need to ever care about.
The 3 User Groups you need to care about are:
Has access to basically everything.
Similar to admins, but lower and with some restrictions in place to be more safe to hand out to more people, since this is like a "power editor" group, it is the minimum required to delete/restore pages for example.
The User Group required to be able to perform basic edits and create pages. To obtain this User Group, request it on the Discord server.