Purchase requisition approval in Dynamics GP is greatly enhanced by using Dynamics GP Workflow. You can customize the approval process, and include both tasks and approval steps.
Approval steps can be assigned to individuals or groups. Approvers can be notified of pending approvals needing their attention within Dynamics GP, or via email.
This is an example of a purchase requisition approval request email message. You can drill down to the requisition, into Dynamics GP, right from the email, or approve or reject it from the email message, without having to login to Dynamics GP:
This is a quick video of an example of the purchase requisition approval process in Dynamics GP:
Here is another video that shows generating a purchase order from an approved requisition: