Yes, Fiat Lux - ASIA is correct, Learner97.

You can add 3 custom fields to your sales forms if you're subscribed to the QuickBooks Online Plus, Essentials, or Simple Start plans. If you want more than 3 fields, you can upgrade your plan to QuickBooks Advanced. 

To add custom fields, you can go to the Custom Form Styles page. Here's how: 

1. Click the Gear icon and click Custom form styles.
2. Select the Content tab and from the sample template.
3. In the header section, select Manage custom fields.
4. In Custom fields, select Add field.
5. Enter the name of the field, and select All sale forms.
6. Enable Print on form so it appears in your form's header.
7. Select Save.

Feel free to use these links for more details in handling your sales transactions: 

• Customize invoices, estimates, and sales receipts in QuickBooks Online
• Create and edit custom fields in QuickBooks Online Advanced

I'll be here if yu have other questions in adding and customizing your transactions. Have a great day!