What do many amateur radio operators use to help form good Morse code characters?

An electronic keyer is a device used in conjunction with a dual-lever paddle to automatically generate perfectly timed 'dits' and 'dahs' (the short and long elements of Morse code). When you press one side of the paddle, it sends a continuous string of precisely spaced dits; the other side sends dahs. This automatic timing takes the physical guesswork out of character spacing, helping operators form excellent, readable Morse code with much less fatigue than manual methods. A straight key requires the operator to manually press and release for every single element and space, making perfect timing much harder to achieve. A DTMF keypad is used for generating telephone tones, and a touchpad is a computer interface, neither of which are used to generate Morse code elements.