Declarative - A declarative sentence makes a statement. It ends with a period.
Example: John is very tired.
Interrogative - An interrogative sentence asks a question. So it would end with question mark.
Example: When does this class end?
Exclamatory - An exclamatory sentence shows strong feeling. It ends with an exclamation mark.
Example: This is so much fun!
Imperative - An imperative sentence gives a command. It ends with an exclamation point or a period.
Example: go to your room and do your homework.