If you want to use the Sunpak DF4000U as a non-camera TTL flash with a Canon camera, you need a set of Canon E-TTL compatible wireless radio triggers or a Canon E-TTL compatible flash / optical controller that can act as a "master" when attached to the camera hot shoe.
The Sunpak DF4000U has a optical receiver who can take the optical pulsed light communication from a Canon "Master" flash, such as a 580EX II or 600EX RT, an ST-E2 optical pulsed light the transmitter or the built-in flash of your Canon EOS 80D.
If the 80D's relatively weak built-in flash is powerful enough for your shooting scenario, you don't need anything else. Set the pop-up flash in the camera as the master (you can also tell it not to fire as the main flash, but only as the flash controller during pre-flash sequences that occur for a moment before opening the shutter) and set the DF4000U to all the instructions called "Canon E-TTL receive mode".
If you need a greater range or to take in a brighter light than the pop-up flash of the 80D allows, you can use any set of Canon E-TTL compatible radio triggers for control the DF4000U off camera. In this case, you need to set the flash as if you were attaching it directly to the hot shoe of the camera – the trigger receiver basically cheats the flash into thinking that it is the camera, everything as the transmitter basically cheats on the camera that it is the flash. Please note that there are many different Canon E-TTL compatible wireless triggers which all use their own proprietary radio communication protocol. You need to make sure that your transmitter and receiver work using the same radio protocol so that they can "speak to each other" in the same language.
An overview of current Canon flash options is available from the Canon Europe website.
A word on why there are no "Canon" or "Nikon" versions of the Sunpak DF4000U:
The hot base of the DF4000U has pins for both Hot shoe contacts from Canon and Nikon. The Canon system places the contacts in a different model than that of the Nikon system. The DF4000U has both sets of pins and the same flash can be used with Canon or Nikon cameras with full E-TTL functionality. Apparently, the DF4000U also has the ability to use its optical receiver to receive optical pulsed light signals from Nikon or Canon wirelessly.