public class Form
{
    public Guid Id { get; set; }
    public string Title { get; set; }
    public List<FormElement> Elements { get; set; }
}

public abstract class FormElement
{
    public string Name { get; set; }
    public string Label { get; set; }
}

public class QuestionElement : FormElement
{
    public string Type { get; set; }
    public bool ReadOnly { get; set; } = false;
}

public class GroupElement : FormElement
{
    public List<FormElement> Elements { get; set; }
}

public class RepeatGroupElement : GroupElement
{

}