If you are looking to manage your expenses type purchases then it helps to categorize them. When an employee enter purchase orders or requisitions then it’s usually difficult to educate them which accounts numbers to use but if you setup categories and provide the navigation for them to find it, they are likely going to find the right category. All you need to be able to do is link the category with an expense account. This you can do in AX in the posting setup.
Here is a quick overview.
AX2012 R3 CU11