Lead time is the time that a product takes to be manufactured or received from a vendor after Purchase Orders are placed. It’s recommended that the buffer be built into lead time, especially if products come from other countries and can have no specific lead times but vary from shipment to shipment.
Lead time can be defined in the Planning Data tab of the Item Master Data screen.
1) From the Modules tab, navigate to: Inventory > Item Master Data
2) Click on the Planning Data tab and locate the Lead Time field: