Can i add Ref number to invoice?

Yes, you can add a reference number on your invoices in QuickBooks Online (QBO), @Anonymous. I'm here to guide you how.

You'll have to create a custom field through the Sales form content section in the Account and Settings page. With this, you can record your invoice's reference number. Here's how:

1. Go to the Gear icon.
2. Select Account and settings.
3. Go to the Sales menu.
4. Click anywhere in the Sales form content section.
5. In the Custom fields section, type in the name (i.e. Ref Number) under the Name column.
6. Select the Internal box.
7. Click Save.

I've attached screenshots below for your reference.

After that, you'll be able to view the custom "Ref Number" field added in your sales transactions. Please note that if nothing is entered in the said field, it won't be included when printing your invoice.

Additionally, you can personalise your sales forms and add the information that matters most to your business. This way, you'll be able to create attractive and professional-looking invoices. For the step-by-step guide, kindly check out this article: Customise invoices, estimates, and sales receipts in QuickBooks Online. It also contains instructions on how to personalise your email message.

I'm also adding this article to guide you in effectively managing your sales transactions in QBO: Manage Customers and income for QuickBooks Online. It includes topics about payments, credit notes, and creating invoices for multiple customers to name a few.

Please let me know if you have other concerns. I'm just around to help. Take care always.