How do I make an item shoot fire charges?

make it where it ignites any block it touches by making it add 1 block of fire and remember to do this in procedure

I mean there is a way to do it, via the command "/summon Fireball ~ ~2 ~ {ExplosionPower:2,direction:[0.0,0.0,0.0]}" but after the fire charge has been summon, you have to manually punch it to the desired destination. If that is ok to you, make a normal item, choose "item on right-clicked procedure"  then choose the Entity Procedure tab, after that select the "execute command in the name of provided entity" Paste the summon fire ball command (which I mentioned earlier) into the blank space, I hope my instruction is clear, good luck! :)

Can't you make an arrow shot at the fireball right after? to prevent bug abusing.

I think that is possible, actually, there is a procedure which allows you to shoot arrow with custom power, knock-back and damage, maybe after you summon the fire ball, an arrow will be shot at the fire charge at the same time but I doubt it will work perfectly

Maybe make a ranged item with fireball spawning.