I want to make a PDF page a fillable application

You may create a fillable PDF and download it from the publish wizard. 

Please refer to the guides below for more information on Fillable PDF creator.

https://www.jotform.com/help/212-How-to-Create-a-PDF-Form

https://www.jotform.com/help/312-JotForm-Fillable-PDF-Creator-with-All-Points

Hope this information helps!