Thank you for reaching out to us here in the community, @Chris2021. Showing your applied credit memo to a customer's invoice is possible, and I am here to guide you on how by using Customer Statement. If you already have your invoice and credit memo transactions ready, let us proceed with making a customer statement.

Here's how:

1. Select +New on the left menu.
2. Under the Others column, select Statement.
3. Select the recipient/s by clicking the Check box.
4. You can preview the statement form by clicking Print or Preview.
5. Select Save and Send once you are ready to send the statement to the customer.

For more details about adding an account summary, I'd like to provide you with this article: Add an account summary to an invoice in QuickBooks Online.

I also want to provide you with these articles as you might need them in the future:

• Manually add transactions to account registers in QuickBooks Online.
• Enter and manage bills and bill payments in QuickBooks Online.

Please reply to this post if you have further concerns about sharing a credit memo with a customer's invoice. I'm always available to assist you.