If you get frustrated when your iPhone screen switches from the upright position (known as “portrait” view) to the horizontal orientation (known as “landscape” view) at the slightest change swivel of your wrist, you may have gone searching for a way to lock the orientation so that doesn’t happen. On the iPad, there is an external button to lock the orientation of the screen, but on the iPhone that same button serves the mute function. Here’s how to lock your iPhone screen so that it is locked in the portrait orientation.