[AC Question]

How do I get the date and time on a galaxy 6 phone?

[tony bag o donuts]

Are you looking for a widget that will display the time?
Do you at least see the time on your device in the upper left corner of the screen in the notification bar?

If yes, take a look at HD widgets, beautiful widgets, etc. which allows you to customize the widget to display information how you want it. Beautiful Widgets has a free version for you to try out and see if you like it. The paid version unlocks additional features.

https://play.google.com/store/apps/details?id=cloudtv.hdwidgets&hl=en

https://play.google.com/store/apps/details?id=com.levelup.beautifulwidgets&hl=en

Here are what some users have experience with:
http://forums.androidcentral.com/samsung-galaxy-s6/521849-best-clock-widget.html