In this video I cover a typical workflow of an employee submitting an expense report and the related approval process. This flow can go many ways depending on how a company manages their expense and payables process. Just to be clear this is using the expense management module in Dynamics AX. There could be expenses that are paid using the accounts payable and procurement modules. If you have a large mobile workforce with company credit cards or where employee pay for expense out of their pockets and want to claim them back then this would be handled by the expense module in Dynamics AX.
The expense module is integrated to the other modules in Dynamics AX. The employee created, configured in the human resource module, the payment to the employee is done through the accounts payable module.
If you want to have a look at the workflow configuration for expense I cover some setup in this post.