How you save the PDF files depends largely upon which browser you are using. We have a useful guide to working with PDF files on our website: https://laviniastamps.com/working-with-pdf-files
Also, this guide covers viewing PDFs in all the popular browsers: https://www.computerhope.com/issues/ch001278.htm
…and of course, there is a free PDF reader (Adobe Acrobat) that can read, display, print and save all types of PDF document: https://get.adobe.com/uk/reader/otherversions/