Infotype Screen Header - Field missing

Hello all

I am new to SAP HR and have an issue which I need to address.

When maintaining employee record in PA30, in infotype 0001 (Organizational Assignment) a field is not showing up on the screen.

The field is "OMNGR_NR" i.e. Personnel Number of the superior.

This field should be visible below Personnel Area and to the right of Employee subgroup.

After doing some research, I believe it is some configuration in Customizing User Interface.

Can anyone guide me through the steps to activate this field so that it is visible on the screen.

Thanks

Vin