Employees are people you want to track, for example, you want to assign items to them. An employee can also be a user (someone who can sign into the Tracker) but doesn't have to be (just as a user can also be an employee but doesn't have to be).
Employees can be primary or secondary assignments (see Tasks and Secondary assignments in Preferences).
Every employee needs a 'number' (which can contain letters, spaces and punctuation marks). If you already have employee numbers, they'll work in the Tracker. If you're interested in integrating Tracker data with your accounting system, now or in the future, use the numbers in that system. But if you're creating new numbers ...
Employees can be imported.
ADD, EDIT AND DELETE EMPLOYEES
ASSIGN ITEMS TO OR PURCHASE THEM FOR EMPLOYEES
Select the items you want to assign to or purchase for an employee in the find and add to cart, fast add to cart or item assignments screens (the Assign to employee and/or Purchase for employee Tasks must be selected in the Preferences screen).
The Employees table contains a large number of user-definable fields. All fields, whether user-definable or not, can be given custom names. So you may see a field in your Employees screen that's not in this list: