Apostrophes (')

Apostrophes have two basic uses in English. They point out either a possession or a  Contraction.

Possession:  In possession apostrophes comes after the letters.
 For example:  father's
                         Ram's
                         the girl's pencils ( one boy has more pencils)
                        friend's  house
NOTE
In plural words end with s  so we have to add only apostrophes at the end of words.
For example: the girls' pencils(several girls have one or more                                                               pencils  )
                        companies' mascot
                        friends' house
           
Contractions: Use of apostrophes in contractions
For example:  He's=  he is or he has
                        you're = you are
                        I'm= I am
                        we'd= we would or we had
                        They've= they have