Hi,The invoice numbers don't shot on the invoice once it has been emailed how do I fix this?

Let me help you sort this out, @ben-mackie85.

I had tried to send an invoice to my email. I was able to receive the invoice with the invoice number on it. 

Actual Invoice

You may want your customer to perform some browser troubleshooting steps to isolate it.

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Internet Explorer: Ctrl + Shift + P
• Safari: Command + Shift + N

If your customer is able to view the with the invoice number, I'd recommend clearing your browser's cache and cookies. However, if you're still getting the same results, you can use a different browser or device. You can check this article to fix unexpected browser behaviours: Troubleshooting browser problems.

Here's how the email looks like when your customer received it:

You can read through this article to learn more about creating and sending invoices to your customer:

• How to email an invoice
• How to change an invoice number

Always feel free to leave a comment below if you have other questions emailing and customising sales form from QuickBooks. I'm always here to help.