Thanks for considering Intuit for your processing needs! The first step would be to apply for a merchant account. This link will take you to a page that goes over our current processing rates for QuickBooks Desktop:
At the top of the page, you will also find a sales number where you can speak to one of our sales agents if you have any questions.
Once your account is approved, you would confer with your website host to determine how to connect Intuit merchant services to your website.
I hope that gets you started!