add custom fields to wp registration

How do i add custom fields to native wp registration form (wp-signup.php)? do you guys offer any plugin for that or is there any way to do it? any code i can past inside wp-signup.php?

By custom fields i mean just to make the form ask for user First and Last name and if possible show a country list.

Note that i dont want to use any form builder plugin like gravity form etc. i want to use the native wp signup system.

I appreciate any help!!