Summary
If you want to post inbound transactions for items with item tracking codes, you might need to assign serial numbers and/or lot numbers. When you post items to inventory, item tracking information is recorded on the item ledger entries.
If expiration dates are assigned to serial/lot numbers when items are inbound, then the items with the earliest expiration date are picked first when outbound. This principle is called First-Expire-First-Out (FEFO).