Galaxy S5 Notifcation Screen

[AC Question]

I'm getting a notification screen when I get email. The screen has the clock at the top, then there is an email icon in the middle. If I touch the icon then the screen shows a dotted circle with a lock on the right and a unlocked lock on the left. The first few lines of the email at the top of the screen. and a list of the other emails at the bottom. Does anyone knows how to turn it off or if it is a system notification or a app?