How to un apply tax to the invoice in quickbooks

Glad to see you here in the Community,

Let me provide steps for removing taxes from your invoice.

The setup of your items will affect your sales tax. To remove the taxes from your invoice, you'll need to make all the items from that invoice nontaxable.

Here's how:

1. Go to the Gear icon, then click Products and Services.
   
2. Select the item and under the Action column, hit Edit.
3. Under Sales tax, click Edit sales tax.
4. Choose Nontaxable to remove the tax, then Done. 
5. Lastly, click Save and close, then Yes.

Do the same to the rest of the items that were listed in your invoice to remove the calculated tax.

Just in case you want to record invoice payments in QBO, you can visit this article: Record an invoice payment.

I'm always here to provide further guidance if you have more concerns regarding your taxes in QBO.