The first manual typewriters were set up in alphabetical order with each character set on the end of a metal bar that struck the paper when each key was pressed but they found a problem. When an operator had learned to type at a fast speed the bars attached to letters that lay close together on the keyboard became entangled.
One way out of the difficulty was to find out which letters were most often used and then place them on the keyboard as far from each other as possible. This had the effect of reducing the chance of tangling the bars and having to fix them before the individual could continue typing. This was how the QWERTY keyboard was born, named after the first six letters on the top line.