iPhone screen frozen on vertical

[bryantsandburg]

my iPhone screen does not change from vertical to horizontal when a turn the phone from vertical to horizontal. How can I fix this?

 

[Reynod]

If you see in the status bar, Orientation Lock is on. To turn it off, swipe up from the bottom of the screen to open the Control Center, then tap . If you have an iPhone 6 Plus or iPhone 6s Plus, turn off Display Zoom to rotate the Home screen.May 31, 2016
If the screen doesn't rotate on your iPhone, iPad, or iPod touch - Apple ...
https/support.apple.com/en-au/HT204547