At the end of a sentence:

Punctuation	Symbol	Example
period	.	I said it.
question mark	?	Did I say it?
exclamation mark	!	Say it!

In the middle of a sentence:

Punctuation	Symbol	Example
comma	,	I said it, but he did not want to hear it.
colon	:	These are the colors: blue, red, yellow, green, purple, and orange.
semicolon	;	I said something; now the silence feels heavier than the words ever did.
quotation	” “	I said “you are crazy.”
apostrophe	‘	I didn’t say that.