Have can I add the service date on an invoice? I added on screen but cannot get to print on invoice

Hello N-mcevilly, 

Welcome to the Community page, 

So when you create and invoice and enter in a service date when you go to print or preview, the service date shows up as date on the invoices on the same line as activity, description, vat and so on. So it is called date and  not service date in the actual pdf invoice you send over to the customer. We hope that clarifies things for you. Any questions please do not hesitate to ask.