can't edit a form

A friend wrote a form for me. It’s a PDF you can fill in and save. I can make my own forms but I cannot save the form I’ve been given in a way it can later be entered. I’ve tried LO Writer and LO Draw but can’t seem to get what I want. If I open this form in either LOW or LOD, after I export it as a PDF it then becomes unable to fill in. Help!

When you export the odt to pdf an option window opens. In the General Tab under General set the Option “Create PDF form”.

Does it matter if the origin of the form is LO Draw or LO Write? I do ceck the “Create PDF form” box