Functions are used when programming button on the POS Screen for the clerk to access.
These can be programmed by going to Setup > POS Screen > POS Screen Setup.
Functions can also be permitted to be used for specific clerks by going to Setup > Clerks > Permissions.
If clerks are linked to a User other than the Admin User, they will be able to be permitted by going to Setup > Users > Modify > Clerk Permissions.