The guitar (along with a few other instruments) needs 2 things to happen just to make one note. Like brass and woodwind instruments which also need 2 things to happen, the guitar needs a finger to be placed and pressed in the right spot (not accounting for the mere 6 open string notes). The ‘other thing’ that needs to happen is the pick striking the right string (the right string deemed to be the one you already have put your left hand finger on) With a brass or woodwind instrument the other thing is blowing into the mouthpiece but there is only one of those on those instruments. With guitar there are usually 6 strings (which we need to find without looking).
I make playing a note on the guitar akin to opening a door. No matter how hard you pull on that door it won’t budge unless you have turned the knob all the way. In guitar the door pulling is the pick action and the knob turning is the left hand fingering. No matter how hard you pick nothing will sound unless the right pressure is applied with the left hand finger(s).