importing existing pdf file (Tablature)

I am uploading pdf files online to convert to an mcsz file. This is tablature only. When I download it and open in Musicscore there is no tab. One file I tried comes up as a music notation page with msiscellaneous rests. The other will not open at all. Am I missing something. I am trying to make the tablature larger so when I import to my Ipad it is easier to read.
Thanks for any help you can provide
Regards,
Riich Perrotta