Thank you for posting in the Community, @hartmanj4577.
Yes, you are correct that deleting an invoice will remove it from the financial statement. Once you delete an invoice, the credit memo attached to it will be Unapplied. This unapplied credit can be used for other open invoices.
Before deleting an invoice with a credit memo, I recommend consulting with your accountant, as this can disrupt your financial records.
When you attempt to delete the invoice, you will see the following prompt.

You can check out this article to learn how to close the fiscal year and prepare for the new one in QuickBooks Online: Year-end guide for QuickBooks Online.
If you have further questions about managing invoices, please feel free to reach out to the QuickBooks Community again. We're here to help. Have a great day!