Ever wondered why those 6 letters made your keyboard formation. Why not they just have the 'abcd' layout instead of the qwerty. Well there are a number of logics behind it. The inventor Christopher Latham Sholes used his brain to the extent and patented this keyboard layout. Now I answer Why QWERTY?
The QWERTY keyboard was originally for typewriters now inherited by the computer keyboards.
The keys were arranged in such a manner that the keys which were pressed consecutively their type heads were placed at an distance so that they do not jam up the type writer. Earlier fast typist used to jam up the typewriters.
Alternating hands while typing is a desirable trait in a keyboard design, since while one hand is typing a letter, the other hand can get in position to type the next letter. Thus, a typist may fall into a steady rhythm and type quickly. However, when a string of letters is done with the same hand, the chances of stuttering are increased and a rhythm can be broken, thus decreasing speed and increasing errors and fatigue. These days almost every phone has the QWERTY layout. In the QWERTY layout many more words can be spelled using only the left hand than the right hand. In fact, thousands of English words can be spelled using only the left hand, while only a couple of hundred words can be typed using only the right hand. In addition, most typing strokes are done with the left hand in the QWERTY layout. This is helpful for left-handed people but to the disadvantage of right-handed people. For example the word "minimum" and "pumpkin" could be typed only using the right hand "TRY IT FOR YOURSELF".
Another fact about the QWERTY keyboard is that you can type a lot of words without leaving the same row like the word "Typewriter" could be typed in the same row without jamming the type heads of typewriters.
