While the Supplier Delivered the Goods. You need to prepare the GRN from Order. You can also do the Direct GRN from the new form.
If you are receiving items along with Batch/Serial Numbers, Expiry/Warranty Date, You can input and save the GRN along with these information.
GRN Also updates your Received Items Standard cost and Purchase cost from the Supplier. Suppose if you have Landed cost add-on, you can able to input additional shipping cost to get your standard cost updated.