To create GST invoice, or to add GST in invoice, please follow the steps below:
The product should be added with tax.
If the tax is included in product, then only invoice will be created with tax.
To add product with tax,
Step 1: Please go to Products & Services.
Step 2: Click on +New Item.
Step 3: Enter product level details, including Tax/GST percentage.
Step 4: Click on Add Item.
Once the product added with GST, please refer to the below article to create an GST invoice by adding the same product added with GST.