When in bank transactions is there anywhere to change the amount of GST $ amount?

Hi alkate, 

QuickBooks Online is the go-to program for business owners that are looking to manage their invoices with ease. It's important you're able to edit your invoice so you can continue to do the things you love. Don't worry, I'll be happy to share more info and make sure you're on the right track with achieving your goals. 

You can edit the taxes on an invoice by clicking on Sales > Invoices > locate and open the invoice in question > from here you can edit your invoice accordingly so it reflects the correct tax amounts. Once you're done, make sure to save your changes. 

There you go! You now know how to edit an invoice in QuickBooks. Let me know if you have additional questions by leaving a comment below, I've got your back,