QB Issue Resolution:
We just need to double check your settings. Please click on the gear icon on the top right, select “custom form styles”. On the custom form styles page, click on “edit”->select the style->click next->select “Header” and make sure “Form number” is checked off->Click save.
Once you’ve completed the steps, your invoice number will show when you print/preview your invoices.
Resolution for Issue 'Why does my custom invoice number not print on my invoice?' available: Yes (Solved).
Source: Intuit Community forum.
Why does my custom invoice number not print on my invoice?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.Support for Company
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!
Error Recovery for Company [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.
Additional Support Options: