A comma is used to separate two words or a group of words, such as:
My estate goes to my husband, son, daughter-in-law, and nephew.
A comma is used to separate two adjectives in a sentence, such as:
He is a strong, healthy man.
Use commas to specify non-essential words or phrases in the sentence such as:
Jill who is my sister shut the door.
The comma is used after a number of words that come as an introduction to the sentence, such as:
Why, I can,t believe this !
The comma is used before and after proper names, a nickname, expressions of endearment, or a person's title when speaking directly to him, such as:
Yes, old friend I well.