How GL Accounts are Picked in FI MM Integration?

There are account assigned and non account assigned scenarios in PO scenario. In accounts scanrios, you have to tell the system the combination of plant, material type, movement type to get the GL.

Plant is assigned as a valuation area in SPRO. Materials type is assigned to valuation class indirectly through account assignments (T code OMSK). This valuation class and plant is assigned in Material master. Now we can group one or more plants with similaiar characteriristcics to diff GL accnts ( T code OMWD).

Now each movement type is assigned business transactions. General modifications are account groupings of this business transactions. You can see the related general modifiere for each movement type using plant, material (T code OMWN).

Combination of Valuation modifieer, valuation class, General modifier in OBYC will give you the GL.