You can select which of these your DPD connection with Shiptheory sends with, as this is an option in your advanced settings of both DPD and DPD Local in Shiptheory. The first step will be to navigate to your DPD/DPD Local settings page in Shiptheory, and scroll down to "advanced settings":
From there, scroll down until you reach the "Customs Charges Responsibility" section, where you will see the two options to select:
A short summary of each of these is as follows:
DAP: Receiver is responsible or the customs charges and pays this on delivery.
DT1: The sender of the order is responsible for customs charges and pays it on their end.
After you've selected the needed option, hit "save" and you should be good to go. If you have any questions here, or run into any issues, please feel free to contact Support.