the first thing we would need is a fighting type move as it is the only type strong against normal

fighting is strong against

--normal

--dark

--steel

--rock

--ice

the next type we would need is a ground type move because it is the only type strong against electric

ground type adds

--electric

--poison

--fire

next would be an ice move because it is one of the few types that is strong against dragon and has the most strengths of the three

ice adds

--dragon

--ground

--grass

--flying

and with that we have 12 types covered leaving fighting, psychic, ghost, water, bug, and fairy left, and as you can tell no single type covers all of these HOWEVER there is something we can do. if our fighting move happens to be flying press, it would add the flying type

flying being added to our fighting move would add

--bug

--fighting

and on top of that if our ice move happened to be freeze dry or freeze shock it would add the water type to the list leaving only fairy,ghost, and psychic left. so unfortunately there is no way to cover every type our final move would be either a ghost or dark move to maximize efficiency but that would still leave fairy. so with the combination of flying press, freeze dry or freeze shock, a ground move, and a dark or ghost move you can be super effective against all types except fairy