When designing an interactive form that has a fixed layout, you need to provide a sufficient number of item lines for users to fill. However, if you wrap the item lines in subforms that are set to flow content, users can add item lines as they need them.Because of the dynamic capabilities of subforms, you can include one or two item lines in the form along with Add and Delete buttons. By wrapping the objects in a subform, you can determine when, where, and how many times particular subforms are repeated by using the options on the Subform and Binding tabs of the Object palette.Wrapping groups of form objects in subforms is an important part of creating a form with dynamic functionality.Subforms contain and control the objects arranged within sections of the form to maintain the form’s layout as it adjusts in length according to the amount of incoming data. Subforms preserve the x and y coordinates of each object to ensure that the objects move as a unit and are placed together.When you wrap groups of objects in subforms, you ensure that, regardless of the amount of data contained in the form, the format of each section and the layout of the entire form will remain consistent and predictable.Remember that end users need to see at least one item row to enter data when they open the form. That means that you must set the Min Count option for the subform to at least 1. Depending on the form, initially displaying two or more rows in the PDF form can give the form a more balanced and pleasing appearance, as well as result in a more intuitive and functional end-user experience.Subforms also provide the dynamic capabilities that let users add or remove rows and sections in the form. For example, you might include various buttons that users can use to add and remove item rows or to submit comments.Plan how you will wrap objects in subforms to create sections in your form design, and then test the form design to ensure that the subforms move and repeat as you intended and do not break across pages in ways not intended.