The biggest adjustment most people have if they try or switch to an iPhone is navigating its buttonless, touch-screen keyboard. Other smartphones have physical buttons, however small, that cell phone users' thumbs have gotten accustomed to. Not knowing where to rest your thumbs and not knowing how the iPhone's screen reacts to touch can be disorienting. It takes a couple days for your fingers to learn a new iPhone-friendly typing pattern. Knowing how to change the orientation of the keyboard helps.
Scroll your applications until you see the "Notes" Application that comes preloaded onto your iPhone. Its icon shows a legal pad. Tap the "Notes" icon, then hit "+" at the top right corner. A blank "piece" of legal pad appears with "Today," the date and time at the top. A keyboard also appears on the bottom half of the screen.
Hold the phone up to you, with the bottom of the phone pointed toward the floor, and turn your iPhone either to the right or to the left so that it is perpendicular to how you were just holding it. By holding your phone in this landscape position, the width of its screen is now wider than it is tall. The keyboard shifts along with the phone, widening so that the keyboard's individual keys are bigger.
Practice typing in the "Notes" application while holding the iPhone in this landscape position. By aiming slightly and directly above the keys, you can type faster and with more accuracy. The iPhone tries to complete certain words before you finish typing them by opening a pop-up box with the word inside. If you want your iPhone to complete the word it is suggesting, tap the space bar. If the word you are typing is not the word your iPhone is offering to complete for you, continue typing your word.