The standard forms provided by most US Bankruptcy Courts are not "fillable" PDFs forms. All you can do is print the blank forms and fill them in by hand with a pen or typewriter. (A what?).
However, in a less obvious place, the US Trustee's Office also publishes fillable PDF versions of the Bankruptcy Forms. These fillable forms allow you to type your answers into the forms. Unfortunately, if you are using the free Acrobat Reader, you cannot save the information you have typed into these fillable forms. (If you own the full version of Adobe Acrobat -- which costs several hundred dollars -- you can save the info you have typed, and return to the form later.)
Fortunately, there are several, free or low-cost software tools for saving fillable PDFs. Some of these low cost products are rather bare-bones, when it comes to interface, but they work. That is, they do provide the option of saving the information you have typed.