This page contains forms that you can customize according to which kind of information you want your users to provide. There are existing forms here as well as a "Create new form" button.
The "Actions" button far to the right of the screen allows you to
- preview of the selected form
- modify the form
- delete the form
When you click the "modify" button, an editor opens: far to the left at the bottom of the screen you can click the HTML button to show the HTML code. Here, you will also be able to pass parameters such as List ID and Group ID, for the user to be automatically subscribed to a specific List or Group.
Code strings look like this:
<input name="group" type="hidden" value="1">
<input name="list" type="hidden" value="2">
In the example above, the user will be subscribed to Group 1 in List 2.
To retrieve Group and List codes, go to Settings > Developer's corner > Codes Table.