I could always choose double-sided printing with my Epson XP-640. That option is unavailable when I try to print from a Mac app.I can still find that printing option with non-Mac apps I am up-to-date on Pages and numbers. Epson shared my screen and worked with m for 1;/2 hr - no go
Normally, there are optional settings available in the print dialog, where you can set it to two-sided printing. Also, sometimes the options change, depending on the version of OS X/macOS. Maybe because the driver is newer in High Sierra, you'll have to explore the settings available.
In the print dialog, just under Paper Size and Orientation, you should see a pop-up selector. Click it, and a drop-down menu should appear with choices like Layout, Color Matching, etc. One of the choices may be Two-sided Printing Settings.