Exclamation Mark (UK) /Exclamation Point (US) !
The exclamation mark or exclamation point shows strong emphasis or strong emotion. It is rarely used in formal writing.

Examples
Stop!
Don’t do that!
I’ve finally finished my assignment!

Question Mark ?
The question mark shows that a question is being asked, that the speaker or writer is seeking an answer to something.

Examples
Can we agree that peace is better than war?
What time does the movie start?
Would you accept a lower price for the watch?

Full Stop (UK)/Period (US)
The full stop or period is the most common punctuation mark in the English language. It has two main functions.

1) It shows the end of a sentence.
Examples
Dinner’s ready.
Sales have increased every month since January.

2) It indicates an abbreviation. This is more commonly used in American English.
Examples
Ms. Jones arrives at 8 to open the office; you can start work any time after that.
Let’s buy a 64-oz. bottle. The kids will be thirsty after playing baseball all day.