Register Lite
This shortcode will provide a simple Register Form with only the Email Address field which is required for the registration process.
The shortcode can be added anywhere in the website, but it will only show up for non-logged users.
There are also some options available from the main Register Form module, which are useful for managing the user registration steps: WP Role, OptIn, Redirect etc. All of these work exactly the same like they do in the main register form module.