What is this proposal link True North sent me?

True North sent me a business proposal — what is it and why do I have to accept it?

True North Accounting uses proposals to outline the services we provide to every client, as well as the prices for those services.

These services and prices are outlined in the proposal and included in our engagement letter, which is electronically signed when you accept the proposal. You can also enter your credit card number to process the payment for the accounting services. 

The proposal must be accepted before we can start the requested services.