How can i add new fields like ( Address, interested fields, Date of birth ) in the registration page of the forum.
wpforo is compatible with buddypress so install that plugin and turn off all features except for register it works I use buddypress on my site just for the register.
I had to use a third-party plugin to create custom registration forms, then I set a custom URL for forum registration pointing to my custom page (and form).
I'm sorry but this is not an easy task and requires lots of customization. You can find some developer and ask to do this or wait for wpForo Profile Custom Fields addon. This is already under development. This is being designed to extend profile fields in account settings, on profile page and on registration page. This will allow to extend registration form using Custom Form Builder with Custom Fields. This will probably be released at the beginning of next month.