The invoice don't put the taxes after the final prices

Good Day  edwinrduque, 

I am happy to help you with this.

Firstly, please ensure that your sales taxes are set up in the Tax icon located on the left corner of your QuickBooks Online portal. 

You can refer to this article in order to do it.

https://quickbooks.intuit.com/learn-support/en-ca/taxes/sales-tax-overview/01/261525

In order to fix your issue, you will need to follow the following steps. 

1. Tap Transactions at the bottom of the app.
2. Tap the transaction you want to apply sales tax to.
3. Toggle Include sales tax to on.

Hope you find this helpful and do reach out of you need further assistance. 

Have a great day!

Hi there. Just to add to the valuable steps provided by AshadH, I'd also recommend clearing cache and cookies just in case you've already set up your taxes. Clearing cache and cookies is a great way to fix browser issues and here's an article that shows you how. Try this out and let me know how you make out.