How to control fields of SAP Business Partner ?
To control fields of SAP Business Partner (BP), you mainly use Field Groupings by BP Role + Customer/Vendor Account Group Field Status
Suppose, if you want the Payment Method field of APP Tab of a Vendor to be made a required.
Either from - Field Attributes of BP Role (NOTE: This is at Client Level)
STEP 1: SPRO > IMG > Cross-Application Components >

STEP 2: Select the Role and click on Field Grouping

STEP 3: Double click on Data Set Vendor: General Company Code Data and then make the Payment method field as required
As you can see below the field is required in BP screen




