Consultants are non-CRS employees who are engaged for short periods to perform a distinct assignment over which they have control. They are not eligible for the benefits employees receive (such as insurance).
The procedure for hiring a consultant depends on where your consultant is from. Click the link below that applies to your situation for instructions on the process.
Hiring a National Consultant (someone from the country where you are working)
Hiring an International Consultant (someone from any country other than the one where you are working)
The origin of the consultant is important because the US has specific tax regulations regarding consultants and employees. Because of this, if you are going to hire a consultant who is from a country other than the country in which you are working, you will work with headquarters to make the arrangements.