How can I create a form in which the user can fill in an ID and password and then prepopulate some of the fields such as address, phone number, etc.

It is not currently possible to log in to forms and have them pre-populate the form after log in.  We actually do not allow for adding username or password fields to forms.  Doing so would likely result in our phishing detector suspending the account.

What you could do, if there are not too many users who would need to have their data populated, would be to set up conditions to update the reset of the fields based on their name or something else:

https://www.jotform.com/help/268-Conditional-Logic-Inserts-Text-Calculation-Into-A-Field