The Dynamics GP Inventory Control module largely works in the background. It has tight integrations to purchase orders, sales orders, vendors, and the general ledger. The inventory transactions generated by and for these modules happens automatically.
However there are a few Inventory Control transactions that are used independently of these other modules. Basically these are adjustment transactions that allow you to adjust inventory quantities and values as needed to maintain an accurate inventory.
There is also an inventory transfer transaction that allows you to move inventory from location to location.
Here is a quick video that shows this functionality in action: