No, if you have already printed your purchased label for a service that requires a printer, no additional documents will be needed. The only exception being the shipment of a parcel to a destination that requires a mandatory customs invoice.
Our shipping platform will ask you if you want to generate a customs invoice to fill in before finishing the shipment or if you will use your own invoice.
Please note that if your shipment is travelling outside the European Union, the Canary Islands, Ceuta, Melilla or Andorra, customs may require more documents. Packlink can't give them to you, since many of them depend directly on the declared content, their value, destination and sometimes even on the investigation required by the customs authority.
For more information about Customs and how to complete this document, please check this article.