What can I do when invoice do not appear on sales by customer report?

Glad to have you here in the Community, @morland-iafrica-.

Let's get your invoice shown on the Sales by Customer report so you can get back to working order.

It's possible that the reporting period isn't set to the specific date when the invoice was created that's why it isn't showing on your Sales by Customer report. You'll want to make sure that the date on the Report period field includes the month of April. I'll attach a screenshot below for your visual reference.

If you can't still find the invoice after changing the reporting period, you'll want to review the Audit log to verify if one of the users changes the invoice date.

You might want to learn how to customize reports in QuickBooks Online. This will help you focus on the details that matter the most to you.

Our doors are always open to help you again if you need further assistance running reports in QuickBooks Online. It’s nice to work with you, @morland-iafrica-.