Exclamation point/mark — !

a.     Use sparsely, mostly in reported speech. Never use double or triple.

b.     Use to mark an emphatic or sarcastic comment.

c.      If an exclamation point and an ellipsis are both required after a statement, the exclamation point precedes the ellipsis.

e.g. It’s on! . . .  See you there.

d.     Treat it like a period/full-stop in quotation marks. If it isn’t part of the quoted material it goes outside

e.g. The traitor betrayed everyone, including his “friends”!