How can I sync with client Wave account ? Do we have an app to accomodate this?

What do you mean with "sync"?

Hi JuliesABCs,

Thanks for reaching out in the QuickBooks Community. QuickBooks Online is a comprehensive program that integrates with many apps and programs. I want to provide you with the available information.

You can import your client's information into a QuickBooks Online account. Check out: Common questions about importing data to QuickBooks Online. You may be able to find a third-party application to help you with syncing your client's account. It's not an option to sync Wave within QuickBooks Online.

You can check the apps to see what integrates by going to the Apps on the left navigation menu. Type Wave into the search and see what may be available.

If you have any further questions about QuickBooks, please ask. I'm here to help. Take Care.