As a fleet manager you are able to give other people permission to also manage the fleet of the company. A user must have an EEVEE account to get access.
You can reach this section via the Settings of the business portal - Accounts & Login.
These are the possible roles:
Admin = 1 person, can manage all settings and configure platform users
Viewer = can view all insights, but not make any changes
A user with admin rights can change this role to Admin (or back to Viewer).