Free Q uickBooks invoice tutorial. Learn how you can create, customize and email invoices in batches to your customers in QuickBooks. Go to Settings then select Custom fields. Select Add field. Enter the name of the field, and select Purchase Order. If you want the custom field to appear on printed and delivered forms, enable Print on form. Select Save. Create an Invoice in QuickBooks Desktop, How To Create an Invoice in QuickBooks, Create an Invoice in QuickBooks Online In your QuickBooks Desktop, go to the Edit menu, then select Preferences. Click Send Forms and go to the Company Preferences tab. From the QuickBooks Home screen or the Customer menu, select Create Invoices.