Clerks will need to be created for each Site that you have in the database.
Head Office has the ability of viewing Clerks from all Sites on the same list, whereas the Sites will only have access to the Clerks within their Site.
When creating Clerks for multiple Sites, you are able to use the same Login Code as another Site.
This enables staff that work in multiple Sites to have the same Login Code no matter which Site they are working in.
Any Clerk that is added at a Site will be added to the Clerks that Head Office can view and modify.
Go to Setup > Clerks > Add/Modify.
Clerks as viewed from Site 2:
Clerks as viewed from Head Office: Notice the field at the top is selected as All Sites. You can also see a culmination of the same Login Codes for some Clerks.