Acctivate does not require the set up of a separate User ID for mobile users. Any User ID set up in Acctivate can login either on Acctivate Mobile or Acctivate Desktop.
Best practice would be to have each employee that will use a Mobile device, login with an individual login to the mobile device, same as on Acctivate Desktop. This assists with determining which user picked a particular order or entered a particular receipt transaction.
Ex. Tom uses TOM as his login for Acctivate on his workstation. He will also use TOM as his login for the Mobile device.
The mobile device will utilize the same user permissions that the desktop application does. So if the user is going to be creating receipts on the mobile device, they need permissions to Modify Inventory Transactions. Review the User Permissions help article for more information on the specific permissions needed.