A contraction is the shortening of a written or spoken word or expression created by omitting one or more letters or sounds. 

Can’t, isn’t, he’s, I’m, we’d, won’t

Some rules regarding usage of contractions:

  • Never use a contraction when you want to emphasize the negative. 
Do not press the Escape key.
  • Avoid obscure or not commonly used contractions like mustn’t, shan’t. It is OK to use contractions for such common words as can’t, it’s, don’t, you’re and the like.
  • Never create your own contractions.
  • Use it’s and its correctly.

Remember, however, that it is easier to read complete phrases than contractions.