To create a user profile in Gorilla Expense there are dozens of fields that are needed (like roles or approval hierarchy or policy limits or mileage rates etc)- typically this information is not present in AAD or Okta. Here are the following ways you can automate user profile creation 

1) We do provide APIs to create and update user profiles. You can consume those APIs via a homegrown program to create/update profiles automatically.
2) You can export our standard employee template on a secure FTP site and we can process it on a daily or weekly basis. Here is the link to our standard employee template  Employee / Manager Data Import Template : Gorilla Expense 
3) If you are using Business Central, we will have a solution for you where you can add Gorilla Expense specific fields on a vendor card in Business Central and we shall then sync the entire profile for you with the user profile in Gorilla Expense. This way while creating a vendor record in BC, you can also create an expense reporting profile by updating additional fields on a single vendor screen in BC, thus streamlining the process.