This is an old question but I need a refresh, if I get a link from a very high DA site , example : https:// highda.com -- 88 DA But the article is on https:// highda.com/jims-blog/ showing no DA on Semrush does this link help me for DA? Is this link worthless?
DA is short for "Domain Authority", not "Page Authority". A link back from an important website is good.
Subdomains are considered totally new sites. No DA of the main sites is passed to the subdomains. If you get a link from highda.com/jims-blog/ page as you said, it can worth a lot depending on how it is linked from the main site. When looking for inner pages, look for PA instead of DA. Inner page links from a high DA site still worth a lot as long as that page is interlinked. highda.com/jims-blog/ is not a subdomain BTW. jims-blog.highda.com is a subdomain.