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Go to Tools > Configure > Configure GST and PST Tax Templates
Fill in your Template Name (i.e. Quebec, Quebec Purchases, Ontario, Ontario Purchases, etc.), GST / HST Rate, PST / QST Rate (if applicable), adjust the Display As if necessary and select the Tax Accounts where applicable
Select Save and you will notice all active templates appear on the lower portion of the screen
See Vendor Tax for additional information on where to apply these templates in your Company Records