Why can I no longer simply add GST to invoices?

One possible reason you're unable to add GST to the invoice is that the feature has not been enabled yet in QuickBooks, info2188.

To enable this in QuickBooks Online (QBO), follow the steps outlined below:

1. Go to the GST menu and select Get started.
2. In the GST section, choose the accounting method and specify the BAS lodgement frequency (monthly, quarterly, annually) based on your business requirements.
3. If your business is required to report Pay-as-you-go Withholding, select the PAYG Withholding box to "tick" it, then define your reporting frequency (monthly, quarterly).
4. If your business is obligated to report PAYG Instalments, select the PAYG Instalments box to "tick it, then select your reporting method (installment amount or installment rate method) and reporting frequency (monthly, quarterly, annually). Visit the ATO website for more information about the reporting method.
5. If you report any of the following taxes, select Other taxes and tick the ones that apply to your business:
   1. Fringe Benefits Tax
   2. Fuel Tax Credits
   3. Wine Equalisation Tax
   4. Luxury Car Tax
6. Click Save and finish.
   
   

Once done with the setup, when creating an invoice, make sure you've selected the Exclusive or Inclusive of Tax to calculate the amount.

Please know that Tax-exclusive is the amount of tax paid as a proportion of the pretax value of whatever is taxed. While Tax-inclusive is the tax paid as a proportion of the after-tax value.

To give you an overview of the type of taxes that you can use, check out this article: GST Overview for QuickBooks Online.

Also, QBO offers several reports to help you access the data you need. You can run the Transaction Detail by GST Codes report to track, review, and analyze GST amounts recorded across transactions. I've added this for you: Run Report in QuickBooks Online.

Fill me in if you have any further questions or clarification when recording GST on the invoice. The Community team is always right here ready to help you anytime.