"rel=nofollow noopener" - Possible to have both at the same time?
"nofollow" tag tells search engines "don't follow this link."
"noreferrer" tag indicates no referrer information to be leaked on this link.
"noopener" tag prevents the new page from being able to access the window.opener property (preventing malicious javascript).
you can use both something like this:
<a href="https://example.com/mypdf.pdf" target="_blank" rel="nofollow noopener">View PDF</a>"noindex" you can't noindex a link. That would have to be defined on-page, in the meta data.
You're better off blocking pages in robots.txt if that's what you're after.
User-agent: * Disallow: /mypdf.pdf