1. Go to the QBO dashboard and find and click Tax menu link found on the sidebar.
2. Click ‘Add/edit tax rate and agencies’ to add new tax and tax rate of the place where you are shipping your products.
3. Click ‘New’ to add new tax name and tax rate.
4. Provide the same details of the tax name tax was configured in Magento.
5. Click ‘Save’ when done.
After finishing the tax setup in both Magento and QuickBooks Online, you can now start mapping the tax rates between Magento and QuickBooks Online.