The specific paper you need to ask for is:
(Application for user registration to La Meva Salut and informed consent) darse de alta la meva salut
If you have a Digital Certificate (idCAT Mòbil or Cl@ve) , you do not need the paper. You can simply go to lamewasalut.gencat.cat , click "Accedeix", and the system will register you automatically. The specific paper you need to ask for