Hi,
There is needed some custom changes in code and in database too, like a sample here for student registration:
components\com_guru\views\gurulogin\tmpl\editform.php
components\com_guru\models\gurulogin.php
function "store" at line 66
and the column in the database - #__guru_customer
Then, all the new fields should be called in required pages, where you need them in the component.