Changing the candidate information page

Changing the candidate information page

Hi - I was wondering if someone could help please. I need to change the format of the candidate information page on Zoho in order to record additional bits of information on them and to refine what we are recording already. My questions are: 1, When I do this, how does it affect all of the past candidate records? Does it delete those fields / boxes (and therefore information contained therein) that are not in our new and revised candidate page? 2, Does it add the new fields to the candidate pages of past records? Any help and urgent response is appreciated.