Is it possible to add Purchasing information to multiple devices at once? I have had a look around and haven't found a way.
You can use the MUT to upload info to multiple devices at once:https://marketplace.jamf.com/details/the-mut/
MUT is the best solution for --> https://marketplace.jamf.com/details/the-mut/
Note: Do not use your Full Admin account in MUT, rather create a new account with limited access which is required for a task and utilised that account with MUT.
Hope this helps..