Currently, we're unable to export customer's contact information into the CSV file since QuickBook Self-Employed (QBSE) doesn't have a customer list.
As a workaround, I'd suggest exporting one customer's invoices via Pdf one at a time. Let me guide you how:
You can also utilize the third-party app offered by QuickBooks.
I also consider that it's a good idea to have the option to export customer's contact information so you can use outside QBSE. Rest assured, I'll take note of this idea. I also encourage visiting our blog to stay current with the latest QuickBooks news and updates.
Additionally, I've added here some resources that you can visit about some How to do I questions in QBSE for your future reference:
Please drop a comment below if you need anything else. I'm always here to help. Keep safe!