Limited fields at registration time and full profile after logged in I want to display limited fields at registration time say username email and password
And when user get registered then he can edit his profile with rest of the fields like Phone no., Address, Date of birth etc.

I tried adding field in admin/config/people
But that fields are visible at the time of registration.

How can I do that any help....
I am using drupal 7
You can do this without installing another module. It's good practice to avoid installing additional modules if you don't have to.

1) Go to the Manage Fields screen for user accounts at admin/config/people/accounts/fields

2) Edit the fields you want to hide/display from the user registration form. There is a setting at the top of the form called "Display on User Registration Form". View the attached screenshot for example.

3) If a field is marked as "required", it has to be displayed on the user registration form.

Certain form fields on the user registration form are not managed through the "Manage Fields" screen. So they can't be changed without getting in to modules. These include username, password, and a few others depending on your set up. But fields that you add yourself, like phone number, address, etc., can be edited.