The above sentence is an exclamatory sentence.
Exclamatory sentences express strong feelings and usually end with an exclamation point (!). Exclamatory sentences are used to express anger, happiness, confusion, love, and any other exuberant emotions.
Imperative sentences usually end with a period but sometimes end with an exclamation point. However, unlike exclamatory sentences, it is used to give a command or ask people to do something.
Declarative sentences are used when you want to make a statement. Its main purpose is to give out information.