I think that converting a PDF file back to a editable one is not a good idea. A PDF file is good for viewing but bad for editing. Conversion back to a editable format is in most cases lossy. The best way is too keep the editable file on your PC and only make a PDF version of your file if you give it away.
But if you do not have the original Word file, than you can use PDF24 to convert PDF files back to Word. This can be done here: https://tools.pdf24.org/en/pdf-to-word