Software: Intuit QuickBooks Desktop accounting software
GST (Goods and Services Tax) is a liability not an income account, hence when you print the Sales by Customer Summary report it prints only the sales amount (excludes GST), which is correct.
You may consider using the Sales by Customer Detail report instead of the Sales by Customer Summary report if you prefer to view the report with the gross amount (amount includes GST) of the sales transaction.
Click the Customize Report button at the top left corner of the Sales by Customer Detail report, and select both the Sales Tax amount and the Gross Amount fields from the Columns window of the Display tab to display both fields on the report.
Rearrange the columns, so you can have the Amount (amount before GST), Sales Tax Amount (GST), and the Gross Amount (amount inclusive of GST) in a sequential order.