setting margins

I haven't found a clear answer and lots of non-responsive answers (e.g. reformat in source document), so here goes

1.  Assume no source document that can be edited in original format.  Just a pdf with words, diagrams, etc, but not having the margins legally required for recording  with county recorder (1" all around).

2.  I want to take the pdf and shrink it as needed to fit onto 8.6 x 11 page with 1" of white space all around the text or diagrams or whatever