Samsung SM-T217SZKASPR - Manual (Page 21)

Rotate
For most screens, you can automatically change the screen orientation from portrait to
landscape by turning the tablet sideways. When entering text, you can turn the tablet sideways
to bring up a bigger keyboard.
Note: Screen rotation needs to be enabled for the screen orientation to automatically change.
Touch and drag down the Notification Panel, then touch Screen rotation.
Tablet Basics 12