Users
Accounts are managed under Admin → Users, including how much space each may use. Admin → Activity log shows who did what.
From the command line
Run these in the folder with your docker-compose.yml.
Set a forgotten password
This also turns off two-factor sign-in and ends the account's sessions and keys. It reads the new password from the input, so type it and press Enter, then Ctrl+D:
docker compose exec -T server /mediarr user upsert you@example.com "Your Name" --admin
Leave out --admin for an account that is not an administrator.
Reset a vault PIN
docker compose exec server /mediarr user reset-vault you@example.com
Delete an account
docker compose exec server /mediarr user delete you@example.com