An exclamatory sentence is one which conveys strong feeling.

An exclamation point  [ ! ]  is used to close such a sentence.

Since any declarative, imperative, or interrogative sentence may be exclamatory if it is expressed with strong feeling, the word-order of the exclamatory sentence may duplicate that of any of the other types.

Copy the examples.
Examples:

He dropped the ball! (Declarative order)

Grab the ladder! (Imperative order)

Is that true! (Interrogative order)

There is, however, one type of exclamatory sentence which has its own characteristic word-order.
In sentences of this type, the exclamatory adjectives what and such and the exclamatory adverb how are used as introductory words. These words and the elements they modify come at the beginning of the sentence; the remainder of the sentence follows in normal declarative order.

Examples:

What tall trees grow here!
    What an entertaining movie we saw there!
          What a long time it has been!
             How wonderful to see you!

Often the remainder of the sentence is omitted , leaving an exclamation which is not a sentence.

Examples:

    What nonsense!

            How horrible!