Remove special feature from a Microsoft Word document that came from a converted pdf

A 20 page PDF file was converted to Microsoft Word by someone with unknown converter, perhaps Adobe Acrobat. I opened the resulting Word document with Word 365. As the file was being edited, the next page doesn't scroll up as expected. Hitting backspace on the succeeding page only result in the deletion of the last letter on the page above. The problem is probably very simple but it is beyond me. I just want the Word document to behave normally without any header and footer nor this "lock" on the page.