What should i do about my horse that won't take the bit?

what you do is have another person with you. while you put the bridle on and put on the bit have someone with your horses favorite treat ready to feed it to him. chances are that he'll take the treat from the person and since their hand is underneath the bit your bit'll go on because his mouth will be open to get the bit so then your getting him to take it + his mouth is opened and he'll be rewarded for doing so.