How to add Nick Names of each person

Answer 1

There is no specific place to put this. You can add nicknames in Bio Notes.

Comments

from a previous post
There are a couple of new options that I think will let you do what you want to do.

There is now an option (under "Show options" at the bottom) to set whether the given name is displayed before or after the surname.
You can also assign a Nickname. The nickname appears in quotes after the given name. You get to the nickname field (as well as Title and Suffix) by clicking the triangle toggle after Name.
You also have (again, under show options) a more fine grained control over what names are displayed on your family tree.

Answer 2

I added (nickname) after the first name