You will need to add all your companies relevant departments for new employees to be able to select from when they are filling out their onboarding online forms.

Add a new Department by selecting the blue 'Add' button, naming the department, and ticking 'Active' 

When you leave 'Active' unticked it will then archive this department - which you can then tick 'Show Archived' and click on the department and tick 'Active' in the archived departments to make that department active again.