In which functional areas are Supplier part numbers created and maintained?

Supplier part numbers are created and maintained in the Product Information Management functional area. This is where you can define and manage items, such as products, services, and components, that you sell, buy, or use in your business processes. You can also associate supplier information with items, such as supplier part numbers, lead times, and prices. Supplier part numbers are used to identify items that you purchase from suppliers or sell to customers using the supplier’s terminology.

References:

Overview of Product Information Management

Manage Supplier Part Numbers