I am very new to Drupal but am good with coding (PHP, JS, whatever is required). I want to set up a simple registration page that allows users to register using minimal fields (name, email, password, etc). ONCE THEY ARE registered and verified/okayed, I would like to give them an OPTION to fill in a profile form, which will have many optional fields they might want to share about themselves.
The profile form will always be available to registered users to edit/change.
What is the best way to achieve this? It seems the PROFILE2 module only adds fields to the registration page.