You can access the site from any device with a web browser and internet connection. Go to https://merchantcenter.intuit.com/ and sign in with your payment account User ID and password.
How do I get my User ID and password?
How you get your User ID and password depends upon your account type and whether or not you completed all the steps in your approval email.
If you use one of the following products, you probably already have a working User ID and password:
QuickBooks Pro, Premier, or Enterprise
QuickBooks Point of Sale (POS) 2013 or later
To find out, visit https://merchantcenter.intuit.com/ and sign in with the User ID (usually your email address) and password you use to sign in to the Intuit product you're using.
If you use one of those products but can't sign in, then you may need to create or confirm your user ID and password. The approval email you received when you opened your account explains how to do so. Locate your approval email and follow all the instructions. For more details, read how to Complete the Intuit QuickBooks payments approval email.