A position is an organizational attribute that describes a user's role (for example, Ramp Agent or Ramp Leader). In a standard AGOA setup, positions are informational and do not by themselves limit what a user can do.
When positions matter
Depending on your setup, positions can also affect what users can see and do:
If Task Access Management is enabled, a user's position can determine which tasks they can view or edit — typically in operational views such as Station View.
In the Backoffice, you only see users with a position equal to or lower than yours. For example, a Ramp Leader can manage Ramp Leaders and below, but not higher positions.
You can edit these users only if they don't have any airline/airport pair or permission that you don't have. If they do, they are read-only for you: you can open them but not change them. See How to edit a user in the Backoffice.
Positions vs. permissions
Positions define who the user is. Permissions define what the user can do. If something seems restricted, it's usually one or the other.