Synchroteam allows you to create invoices for customers and it also allows you to export them.
To do this:
Click on "Invoices" in the menu
You can search (1), click the checkboxes (2) for the ones you wish to export and click the "Export CSV" button (3)
The "Invoices.csv" file is automatically downloaded.
Important! In the CSV file, each line represent an invoice line, not one invoice. This is why you can have multiple lines for one invoice.