Interrogative sentences ask questions- example:- who is that boy?, what is your name?
Exclamatory sentences show huge grief, wonder or a wish-example:- I wish I was there!, what a beautiful picture!, alas! He is dead.
Imerative sentences command , order, request-example:- go to study, bring me a glass of water, please do the work.
Affirmative sentences make a statement-example:- he is a boy.