How can I identify which columns in the CDIF are mandatory and which are optional?

Created by Atif Ikramuddin, Modified on Wed, 27 Aug at 1:31 PM by Atif Ikramuddin

In all tabs of the CDIF, the columns with white background are mandatory, while all other columns are optional.
Refer to the screen-print below for visual guidance: Column A (Supplier Name) is mandatory.