Odoo has a default “admin” account as standard (with a default password, which you should definitely change on any production database).

1. In Odoo 11 and earlier, “admin” was automatically a “superuser“. In Odoo 12 and later, it needs to be activated (see below).
2. Also, the “admin” account used to be the only one that worked across multiple companies, which is both useful and dangerous. It was therefore recommended NOT to use the “admin” account to enter transactions.
   • In Odoo 13, multicompany has been re-designed, so any account can access multiple companies and it should work properly.
3. In all versions, the “admin” account is (by default) a member of all application security groups, which is another example of “useful but dangerous” (and should be used with care).

Admin (User setup and Settings)

The “admin” account is traditionally used for system admin, but any user can be added to one of the two user access groups:

1. “Administration / Access Rights” to setup users
2. “Administration / Settings” to setup users and change system settings

Super User

There are several ways to (temporarily) become a “superuser”:

1. In Developer mode, an admin user (in the Admin / Settings group) can click on the “Become Superuser” option in the developer menu. 
2. In Developer mode, click on “Login as superuser” in the login screen.  
3. Or there’s a shortcut: http://your-domain/web/become

When “superuser” mode is enabled, the current user is shown as OdooBot, and the colors in the upper-right area change to yellow and black stripes.

You can’t (as far as I know) switch off “superuser mode”, so you have to log off.

Record Rules

Some Odoo documentation used to state that the “admin” account was not subject to Record Rules. This has now been corrected to say that in superuser mode you are not subject to Record Rules (as explained above, the two used to be the same thing).

The admin account is assigned to all access groups, but this can be changed.

Technical information

In Odoo v11 and earlier, the “admin” user can be identified by UID = 1

In version 12 this has changed to UID = 2 and as superuser the account name changes to OdooBot and UID = 1.