Everyone employed full-time or part-time, on a permanent or temporary basis, to perform work in your business in exchange for compensation should be added to your list of employees." 

Are there exceptions?

Yes, there are two exceptions:

Consultants and subcontractors

Consultants and subcontractors are not exclusive resources to your company, i.e. they have different customers to whom they provide services. Their cost should not be budgeted using the menu "Employees" but in the menu "Expenses". For example, a graphic designer should be budgeted under the category "professional fees" of the menu "Expenses".

Production labor

When an employee is hired only to produce goods for sale, it is called production labor, i.e. that the labor is directly related to a production process.

Here's an example:

A company manufactures "Product A". Each unit of "Product A" requires one hour of assembly. The cost for labor is 10$ per hour. When planning your sales, each unit sold will cost you 10$ of labor. This labor must be budgeted directly into the configuration of your "Products" in the menu "Revenues". You do not need to add them to your list of employees since their employment is directly related to the fact that you are manufacturing because you have sales.

No sales = no production = no production labor.

Warning: Your "foreman" may seem to be production labor. However, if he is employed and paid even if there is no production, then he is an employee and must be budgeted using menu "Employees".

Related article: How to add Expenses