Well you can create/edit a form in a view class file(located at /view folder or admincp/view folder), and use Mysidia's Form or FormBuilder class. Below is an example of how to use the form builder:
The above example creates a login form, similar to Mysidia's login form. You can look into the file class_form.php and class_formbuilder.php to see what methods these classes have for you to create a form dynamically.