Hi @Rafael_Calvo - not sure what your base setup is, but from the description, I’m guessing the user will choose a person and add some additional information about this person - is that right? From what you say, the people are pre-defined and come from first and last name fields. To achieve this I would have two tables - one for the people:
and one for the form data:
In the form table “person” is a linked field.
Then in your form you can do exactly as you describe: