I'm so glad that my colleague was able to able to help you. You can count on the Community if you need additional assistance in completing your other tasks with QuickBooks.
It's always our pleasure to help. Cheering you and your business to continued success!
Recovering the deleted invoice in QuickBooks Self-Employed (QBSE) is currently unavailable. With this, I'd suggest re-creating it manually in your account. If you've sent the invoice before to your customers, you might want to ask them for a copy for your reference.
Once you have done creating the invoice, you have an option to copy, export as pdf, and send the transaction to your own email for your back up.
See the screenshot below for your reference:
Additionally, browse through these articles below. It contains different topics on how to manage customer's transactions, invoices, reports using a browser, and mobile apps.
I'm so glad that my colleague was able to able to help you. You can count on the Community if you need additional assistance in completing your other tasks with QuickBooks.
It's always our pleasure to help. Cheering you and your business to continued success!