Use Transaction MIGO. Enter the Header Data, select the Movement Type, Enter the PO Number, select the PO items to be copied, and then post the document.

Now, How can you post a Goods Receipt if the PO number is not known?
If you selected PO Number Not Known in Transaction MIGO, you can specify search criteria for the POs on the initial screen. The system then displays a list of purchase orders. Select and copy the required PO items.

If you like this post, you may as well like these too:

1. Goods Receipt Process for Inbound Deliveries The goods receipt process for inbound deliveries is an essential part of the supply chain. This process includes the steps after creation of the purchase order: notification, the inbound delivery,...
2. Perform Goods Issue Use Transaction MIGO. On the initial screen, enter the header data (you need not enter the Movement Type or the Plant as these are automatically copied from the order). Choose...
3. Perform Invoice Verification If the Invoice refers to an existing document (PO, etc.), then the system pulls up all of the relevant information like Vendor, Material, Quantity, Terms of Delivery, and Payment Terms...
4. ABAP Programs:External perform call This is the simple code which will show you as to how you can call the external routine from the current program. Program 1 REPORT ZSOURCE2307. * List of the...
5. ABAP Program: Dynamic external perform (call back form) Here the two programs which are calling dynamically. REPORT ZSOURCE2309. PERFORM EXTFORM IN PROGRAM ZSOURCE2310 USING 'CALL_BACK_FORM' SY-CPROG. FORM CALL_BACK_FORM. WRITE / 'I am the call back form in ZSOURCE2309.'....