Exclamation point (!)
The main use of the exclamation point is to end sentences that express:
Ow! That hurt!
Hello! How are you?
direct speech that represents something shouted or spoken very loudly:
"Look up there!" she yelled.
something that the writer finds amusing:
Included on the list of banned items was 'crochet hooks'!
An exclamation point can also be used in parentheses after a statement to show that the writer finds it funny or ironic:
He was upset because he had forgotten to set his VCR to tape the Flintstones retrospective(!).
People tend to use a lot of exclamation points in informal writing such as e-mails or text messages, but you should avoid using them in formal writing.