How to add field in field
I think you're looking for the Double field module.


  Double field is a small module written to provide extensions to Drupal's core Fields. By this module you can divide your fields into two seporate parts. For the moment it includes the following sub-widget types:
  
  
  Textfield
  Select list
  Single checkbox
  Textarea Consequently, in all there are 4 x 4 = 16 widget types.
  


Currently it is not supporting file upload. However, you can make this as support request in that module's issue queue.