Shown here are the main kinds of guitar, but there are more: Baritone guitars have just four strings; some resonator guitars have a metal body; some nylon string guitars can have electronic amplification; resonators have a round speaker-like device that amplifies the sound. Some guitars have 7 or even 10 strings; some have two necks, one six-string, the other 12 string.
All guitars are played in the same way and the fretboards are all laid out in the same way. 'Acoustic' guitars rely solely on their construction for volume, whereas electrics rely either totally or partially on electronics for theirs. Solid body guitars were invented to prevent "feedback", which is that howling sound you hear when microphones (or pickups) start re-amplifying their own sound. Because they get their volume from the pickups, the strings used on electric guitars can be very thin, making it much easier to play fast and to bend. Steel string acoustics need heavier strings to be heard properly, and are therefore a little harder to play at first. Your finger tips do toughen up, though, with regular playing.
Beginners often choose nylon string guitars because they're friendlier on the fingers and have a wider fingerboard making it easier to grab chord shapes.