There seems to be a large amount of people who bought the Apple iPhone or iPad who have problems with the unit magnifying the screen 2X and making the graphics huge to a point where the screen is too big to be usable.
Apparently this is a feature with the iOS operating system. What has most likely happened is you may have accidentally enabled the zoom feature by double tapping it with 3 fingers.
To fix this issue, simply double-tap on the screen again with 3 fingers and the screen will usually go back to normal and eliminate the magnification.
If the double-tap doesn’t work for you, try double tapping again, only on the second tap, keep your fingers on the screen, then drag them up and down to zoom in and out respectively.
If you want to disable this feature and prevent this problem from happening again, you can go to “Settings” > “General” > “Accessibility” and turn off “Zoom“.