The TCode MB01 in SAP is used to post a Goods Receipt (GR) manually, typically against a Purchase Order (PO) or without reference, depending on the process.
MB01 – Post Goods Receipt
This is part of Inventory Management in the Materials Management (MM) module.
Note: MB01 is older and has largely been replaced by MIGO, which offers a more user-friendly and versatile interface for all goods movements.