Good day, tony93.
For the time being, we're unable to restore a deleted transaction. However, you can retrieve the information in the Audit Log report.
Please see this sample screenshot for a visual guide:
Once you have the details, you can proceed in creating the invoice. Feel free to check out this article that includes a video tutorial: QuickBooks Online - Invoicing and quoting tutorials.
I'm here if you have more questions about invoices or other concerns with QuickBooks Online. Take care and stay safe.