This article explains how to determine whether a company is a vendor, a customer, or both.
Procedure in the FM Portal
Path to the starting point: Basic Data - Companies & Addresses
Open the company record you want to determine.
Click on Additional Data in the toolbar.
If you see an entry here labeled "Details on the Debtor," then the company is a debtor. If you see the entry "Details on the Creditor," then the company is a creditor. If both entries are present, the company is both.