HP LaserJet Enterprise M806 Printer series - Manual (Page 45)

Automatically print on both sides (Windows)
NOTE: Your print driver might look different than what is shown here, but the steps are the same.
1. From the software program, select the Print
option.
2. Select the product from the list of printers, and
then select Properties or Preferences (the name
varies for different software programs).
3. Click the Finishing tab.
ENWW Print tasks (Windows) 37