The article below provides helpful colon usage rules and examples.
What Is a Colon?
A colon is a type of punctuation mark that lets the reader know that an explanation or example will follow. Writers use a colon in many different situations.
Using a Colon to Introduce a List
One of the most common uses of a colon is to introduce a list of items. Remember not to place a colon directly after a verb, a preposition, or the words because and as , though. Instead, rephrase the sentence.
Colon Examples:
To Introduce a Quotation
Use a colon to introduce quotations that are either formal or lengthy.
Quotation Colon Examples:

A Colon between Independent Clauses
Use a colon between two independent clauses when the second clause provides an explanation or summarization of the first clause.

Other Common Colon Uses
Use colons after greetings in business letters and after labels that call attention to important ideas. Also place colons between the hours and minutes in a notation of time and between chapters and verses from certain religious texts.
I am writing to express my interest in the position of sales associate.
Check out our free, printable Colon Worksheets!