The normal way to do this is to add that user to the sudoers file. You can do that this way:

• Open a terminal and type

  
  
  

  sudo su
  
  




• After entering your admin password type

  
  
  

  visudo
  
  




• Using the arrow keys, navigate to the bottom of the sudoers file that is now displayed in the terminal




• Just under the line that looks like:

  
  
  

  root ALL=(ALL) ALL
  
  




• Add

  
  
  

  amira ALL=(ALL) ALL
  
  




• Now press Ctrl+X and press Y when prompted to save

User amira can now use sudo to edit file, permissions and anything an admin user (like the one you used installing your Ubuntu) is capable of doing.