I am wondering, can someone see if or when you used Google Hangouts last? Like say I was on there today. Can someone see that I was on there today? If so how do I turn this off?
Yes, people can see when you were last seen online. See this Hangouts Help to know how it works.
You can change the general settings for the app, like notifications and when you were last seen online.
- On your Android device, open the Hangouts app.
- At the top left, touch Menu.
- Touch Settings.
- Touch your Google Account.
- Choose the setting you want to change.
For more details see this -> Change your general Hangouts app settings.
To change Hangouts settings on a computer see this -> Change Hangouts settings on a computer.