Q: holy flippin moly

The lock / power button at the top should do it. Unless that's not what you mean?

I'm not sure what iOS you are running in which iPhone, but if you are asking about screen rotation, your either double tap the home button to find the rotation lock or on a newer iPhone running a much later iOS version, swipe up from the bottom of the screen to get to the control center where you can find the padlock icon.

Older iOS

https://www.ifixit.com/Answers/View/75026/unlock+auto+rotation+on+iPhone+screen

For a picture of the control center.

If the screen doesn't rotate on your iPhone, iPad, or iPod touch - Apple Support