Invoice # not show in customers page

I'll share some solutions to help you with your concern, numan-appsgenii-

If the No. column is missing in the Customers page, we can add it to show the invoice number.

Here's how:

1. Go to Sales > Customers.
2. Click the Gear icon above the Action column.
3. Put a check mark on the No. box. The will appear after checking the box.

Please see this sample screenshot for a visual reference:

Otherwise, we can perform some troubleshooting steps to rule out any browser-related issues. To start, open an incognito or private browser. This mode prevents your browsing history from being stored. You can use the keyboard shortcuts below: 

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

Next, go to Sales > Customers. If you're able to see the invoice number in the No. field, then let's go back to your regular browser and clear its cache. Finally, restart your browser. 

On the other hand, try using a different supported browsers. If you need help with other task in QuickBooks Online, you can check out our articles in the general help topics page.

Please let me know how it goes. I'm here to help you out again. Thanks.