There is 4 sentence types: Declarative, Imperative, interrogative, exclamatory.
-The declarative type, as it name says, it declares something, state a fact, claim something, there's no feelings in it or a question, nothing: You're just stating something.
Example: I'm eating an Apple.
-The Imperative type states an order, or is used to give advices.
Example: Do Your homework.
-The interrogative type is used to ask questions.
Example: Do you like apples? Did you do your homework?
-The exclamatory type is used to express emotions like anger or happiness or surprise etc...
Example: This apple is so delicious! That's such an amazing view!
Hope this Helps! :)