How can I invoice a different customer for a work done?

In STEL Order you have the option "Invoice to", with which you can assign a different customer than the one you indicated in the document.

That way when generating the invoice, it will show the name of the customer that you indicated in that field.

Remember the option "Invoice to", is only available in the SAT module, so you will have to indicate it in a quote, order or delivery note so that when generating the invoice the change is applied.