What does "P. S." means and stands for in emails and letters?

It means post script. post means after thats why we use it after the message or letter for additonal information

P. S stands for post script.

P. S means a small short little ending for when a letter or email or message is done.

Ex: Lets all go shopping at the city mall. We'll have so much fun.

PS: Don't tell your little brother we are buying ice cream! : >)