Hi there Adb2,
Including the GST on your supplier bill ensures that you're most accurately tracking the sales tax that you pay on purchases. It's a straightforward process when you're using QuickBooks Online and I'm happy to go over it with you.
The first important step to ensuring that you'll be able to add GST to your supplier bill is to make sure that you've set up sales tax in QuickBooks Online. Navigate to the Taxes menu and select Sales Tax. If you haven't set it up yet, follow the prompts on screen to set up the appropriate tax agency and tax codes. If you've already got sales tax set up, you can move on to the next step in the process. Here's where you can learn more about How to set up a new sales tax code.
Next you can enter the supplier bill. To do that, hit the + New button and choose Bill. Select the appropriate Supplier from the dropdown menu, adjust the terms and dates accordingly, and enter the Category or Item details. You should see a Sales Tax column on the far right. That's where you'll want to select the correct sales tax code to apply to the bill.
You've indicated that the gst is included in the bill, so that leads me to believe that the price your supplier gave you was Inclusive of Tax meaning that you got one price rather than a breakdown of the items or services plus the tax. To be able to correctly enter that you'll need to use the dropdown above the Sales Tax column that reads Amounts are and select Inclusive of Tax. Now the amount that's calculated will show the tax as being incorporated in the given price.
Once you're finished you can hit Save and close at the bottom of the window to save the new bill. I know you'll get the hang of this in no time, but don't hesitate to drop another line here in the Community when you need a hand. Have a great day!