Thanks for posting your question on Justanswer.com, a global paid independent support site.My Name is ***** ***** I will be assisting you today. Please follow the steps below and let me know, how it goes for you. I am posting these steps as I do not know, what you have tried so far.
Open any document.
Click File-->Print, In the print dialog box click the properties button > Click the page setup tab
Look for duplex printing option, enable it and press OK and then try to print.