Drupal7 - User/Registration customizing Please any one help me to how I can do customizing User/Registration page in Drupal 7. For example I have a select option for user group, suppose if I choose 'others' option ’ then user is allowed to create new group in separate text box.

I'm new to Drupal. Please anyone help me
In Drupal 7 you can use Select (or other) module for your requirement


  Select (or other) module : Provides a new Forms API element which is a select/radios/checkboxes element that has an 'other' option. When
  'other' is selected a textfield appears for the user to provide a
  custom value.