It is best to assign an SSCC immediately after the logistic unit has been composed.
The producer can therefore already assign the SSCC at the production output of the finished products. Has the producer not assigned an SSCC? Then the wholesaler can do this upon receipt of the goods. This is best practice for homogeneous logistics units that contain only one product with one lot number.
However, heterogeneous logistics units containing different products can only receive an SSCC during picking. During that process, the relationship between the products, their GTIN, their lot number and the carrier is established.
The SSCC is printed on a logistics label that is affixed to the logistics unit.
Everything about the GS1 logistics label