Do-follow links:
Do-follow links allow the search engines to follow them and reach a website. They act as backlinks that are counted by search engines and help in enhancing the ranking of a site. By default all the hyperlinks are dofollow.
No-follow links:
A no-follow link tells search engines to ignore a link. It does not pass any value from one site to another. Usually, it does influence the ranking or visibility in the search engine index. A no-follow link contains a rel=”nofollow” attribute in its HTML code.