how to be a quickbooks online proadvisor and how much does it cost

You need to sign up for Intuit Accountant Suite to be a QuickBooks Online Pro Advisor. Once done, you can go to your account to start your training and take the exam to become a certified ProAdvisor.

To learn more about pricing and plans, I recommend visiting this website: Intuit Accountant Suite Plans & Features.  

If you have other questions, feel free to comment below.