There are four kinds of sentences.
Assertive or Declarative Sentence
A sentence that makes a statement or assertion is called an assertive or declarative sentence. Assertive sentence ends with a period.
Examples
He goes to school
He likes to play chess.
They are singing a song.
Interrogative Sentence
A sentence that asks a question is called an interrogative sentence. Interrogative sentence ends with question mark.
Examples.
Where are you going?
Do you use your laptop?
Imperative Sentence
A sentence that expresses a request, command or advice is called an imperative sentence.
Examples
Open the door.(an order)
Please help me(a request)
Exclamatory Sentence
A sentence that expresses strong feelings or emotions is called an exclamatory sentence. These sentences express surprise, joy, sorrow, appreciation, love excitement, frustration, anger etc. An exclamatory sentence ends with exclamation mark.
Examples
What a beautiful flower it is!
How nicely she is singing!
That is fantastic!
Hurrah! We won the match!