Paragraph Styles/Content Field in InDesign instead Text Field for interactive PDF

I design interactive letter pad (PDF). I tried applying Paragraph Styles / Content Field in InDesign CS6 that user can compute data and write paragraph. Text field is only an option in the inDesign for compute text, but it is not useful in this case because  a single text field only appears (in export PDF). I need to write paragraph . How to do that?

Thanks