Marshmallow has not been a huge update in terms of new features. In fact their are only a handful of new features. Changes have been mostly in security and aesthetics. One of the most interesting new features is the Google Now On Tap. If using the Google Now launcher it allows you to long press the home button to bring up search results based on the content displayed on your page. Google has just updated On tap with a "share" option. If you press and hold the home button to bring up on tap you will notice a share button in the bottom left hand corner. Pressing the share button takes a screen shot of your current screen and gives you options to share. The only downside here is that it is indeed Marshmallow only.