Hello there, solace-marine.

Thanks for reaching out the Community. I'm here to help restore a deleted invoice in QuickBooks Online (QBO).

Restoring a deleted invoice would be a great option in QBO. However, this hasn't been made available within the program.

You'll want to recreate the deleted invoice. To get the detailed information of the invoice, you can use the Audit Log. 

1. Click on the Gear icon.
2. Select Audit Log.
3. Click on the Filter drop down.
4. Set the date range and choose Show only these events under Events.
5. Click to Select Transactions.
6. In the Show drop down, select Deleted/Voided Transactions.
7. Click on Apply.

Then, recreate the invoice as new with its original transaction date using the information from the Audit Log.

For further guidance, you can refer to this article: Restore deleted transactions.

These steps should help you restore a deleted invoice by recreating it.

Please let me know if there's anything else you need. I'm here to help. Take care and have a great day.