If you are using purchase requisitions there are may different types of materials and therefore potentially workflows that you might go through in your organization. Sometimes you want to add control to reducing purchasing sometimes you want to add control to identify the right vendor to purchase from. So while you might have a manager approve a purchase requisition you might not want to have it created as a purchase order immediately after the approval.
For example if you have a requisition that doesn’t have a vendor then you won’t be able to create a purchase order so it will have to sit and wait for purchasing to review it. As well you might have a policy that you don’t have purchase orders created automatically or only created under specific conditions.
You have a lot of option on how you set this up with the workflow and with the purchasing policy that you can find under the rule for purchase order creation and demand consolidation. The parameter is called manual purchase order creation.
Here is a quick overview.
AX2012 R3 CU11.