Unless otherwise indicated, all hyperlinks are dofollow links by default. When crawlers from search engines come upon a link, they crawl the page and pass the link juice forward as a vote of quality. Because dofollow links from high-authority sites are excellent backlinks, they will help a site rank higher in SERPs.
Nofollow links are designed in such a manner that they are not crawled by search engines or counted as quality votes. When you wish to connect to third-party websites on your website without giving them authority, you may utilize this.