Hi there maylenn7-gmail-c,
It's important that all your clients' transactions are entered correctly for their books to be well balanced. QuickBooks Online Accountant is a great tool able to help you connect with your client's books so you can help them make sure all is entered correctly. I can provide some information about QuickBooks Online Accountants.
The Canadian version of QuickBooks Online Accountant is only able to connect with clients that have a Canadian subscription to QuickBooks Online. If you're looking at connecting with American clients, you would need the US version of QuickBooks Online Accountant. To see if it would be possible to advertise with a Canadian address on a US ProAdvisor profile, I would recommend speaking with the US support team to make sure it's possible. You can also post on the US QuickBooks Community by clicking on the linked website.
if you have any other questions, feel free to reach out here.