The invoice number does not show on the actual invoice document
Thanks for joining the thread, RogerM.
Aside from checking the Form numbers, we also need to make sure that you've selected the correct template. Create an invoice as usual. Click on Customise button at the bottom. Then, select your customised template. You can also follow these steps to make it default:
Go to Custom form styles.
Locate the invoice template. Click on the arrow beside the Edit.
Select Make default.
Let's perform these steps if what you'd like to achieve is to show the Invoice no. field when creating it. This field won't appear on the invoice page if this option isn't turned on. Though, it'll still show when previewing it since QuickBooks will automatically generate an invoice number.
From the Gear icon, select the Account and Settings.
Select the Sales tab. Click on the Sales form content section to expand it.
Check the Custom transaction numbers box. Then click on Save.