Create two entities: form and input.
At the ‘form’ entity you store basic information regarding the form and can have many input entities as association.
At the entity named ‘input’ you use an enum to define the type of input and then use visibility on the page itself to define what to show (you can use the enum for that).
Then you can create a button on the page where you show the form dataview where you can create new input fields. This can be done by adding for every input type a button or create a popup where you ask the user what he or she wants to add and move from there on.
It also seems you keep asking over and over the same question, you should update your question. It might also handy to share some screenshots from what you have created and where you struggle. So people are able to give you more detailed help instead of what you are doing now.