When doing business with an IR35 umbrella company it will work to help you out in many ways. This is so you can focus on the task at hand of working as a contractor.
First the contractor umbrella will work to handle the contract that you have with a recruitment agency. The IR35 umbrella company will deal with the communication between you and the agency.
Also, the invoice that you send out to the IR35 umbrella provider will be sent out to that agency. The provider will collect your money and give it to you at a proper schedule. This is so the provider can calculate your deductions and treat you as an employee that does not have to deal with IR35 expenses.
In addition to this the company can work to help with handling some of the money that you have for later payments. This is so you can get money during times when your contractor business is slow.