Transfer In -  This is for when an transfer is being accepted by the receiving shop/store.

Purchase Orders - Used when a PO has been delivered and being accepted into the shop/store.

Auto Receive Transfers In - This is when an transfer can be received automatically this is a faster way to accept transfers. 

Auto Receive Purchase Orders - This is when an PO can be received automatically this is a faster way to accept PO.

Click & Collect - When a item has been Ordered for Click & Collect and it arrives in store this is used to scan the item.