Hello ysong17,

Thanks for getting back to us. That is correct. If you're not registered for GST/BAS you can set all expenses to Out of Scope tax code to not calculate GST on the transaction. 

Also, you can check this link to learn more about the GST in QuickBooks Online: GST Central.

As always feel to post a comment below if you have more questions about QuickBooks Online. The Community is here to help you.