How do I change the currency type? It's currently NT but it should be USD.

I'm glad to provide some insight into your multi-currency issue, lucilla32. 

In QuickBooks Online (QBO), once you've already turned on multicurrency and selected a home currency, the option to change it is unavailable. This is to avoid messing up the account, especially when adjusting the sales tax. 

In case you've already turned on the "Multi-currency" feature, you'll need to cancel the subscription or get a new QuickBooks Online account.

Here's how to change your currency:

1. Go to the Gear icon.
2. Select Account and Settings.
3. Go to the Advanced menu.
4. Click anywhere in the Currency section to view its content.
5. Turn on the Multicurrency feature.
6. Choose the home currency. 
7. Once done, click Save and Done. 

You may want to take a look at these write-ups to learn more about multi-currency in QuickBooks Online:  Turn on and use multicurrency

You always get back to me if you have any other multi-currency concerns. I'd be more than willing to lend you a hand. Have a great day. 

@lucilla32 

Where is your company located?