Hangouts Option menu

From the chatting list, tap the Menu icon (at the upper-right corner of the screen) to choose from Set mood, Invites, Snooze notifications, Archived Hangouts, Settings, Send feedback, and Help.

While chatting, tap the Menu icon (at the upper-right corner of the screen) > choose from People & options, New group Hangout, Turn history off, Archive, Delete, and Help & feedback.