Printing & emailing lists is available from the Web app and Mac app as well as on iOS & Android devices.
On Mac & Web
Select the list you wish to print and then select "More" from the Action Bar (located either at the bottom of the screen in Mac, or in the top right for Web). Here you have the option to print or email the entire list or selected tasks:on Mac: in Web:
On iPhone & iPadTo print or email from your iOS device, first open the list then tap "More" from the Action Bar at the bottom of the screen. Here you will find options to print or email your list.
Note: Though these features are not yet available on Windows 10, we are working toward introducing this across all client platforms.