All links are automatically dofollow. When links are dofollow, it means it passes authority and confidence vote, often called "link juice", to the web page that it links to.
A nofollow link passes no link juice to the linked page, thus has little or no help in boosting a web page's ranking. The nofollow attribute is designed to combat link spam by preventing the passing of link juice, thereby reducing its impact on search engine ranking.
Since 2019, Google has also introduced two new link attributes that further segment the catchall nofollow link: sponsored and ugc
Dofollow indicates that the linked document is endorsed by the author of this one. Dofollow is the default rel value.
Nofollow indicates that the linked document is not endorsed by the author of this one.
Sponsored indicates links on a site that were created as part of advertising, sponsorships or similar agreements.
Ugc indicates links that appear within User Generated Content, such as comments and forum posts.
Right-click on your browser and click "View page source". Next, look for the link in the HTML of the page. If you see a rel="nofollow" attribute, that link is nofollowed.
If you want to scan all pages of a website and classify dofollow and nofollow links, you can use Vovsoft SEO Checker on your Windows PC. This software is an easy to use website crawler, able to find broken links, distinguish internal and external links, analyze internal linking, titles, description meta tags and more.