The client needs to create a custom entity field in the employee record and the field should show in the primary subtab.
Solution:-
Create a custom entity field.
Customization> List/ records> entity field
Add the field in the employee record by clicking the checkmark in the employee
Add details
Click save.
Now it will show in the custom tab.
To add this in the Classification
Customize the form which you need to show.
Change the entity filed to main subtab.
Click save.
Now the entity field shows in classification section.
