Now that we know about backlinks, we need to know about what are the types of backlinks that are posted on the webpages and what are their significances, lets check them:

There exist two types of links:

Do-follow links and No-Follow links.  

Though both types of links give similar results, still knowing about them is never a harm. 

Do-Follow Links: These types of links help in passing the authority of one site to another. This is called the passing of 'link juice'. Do follow links help in passing one website's domain authority to another website, which later helps in building keyword authority and hence results in an improvement in SERPs. 

No-Follow Links: These links do not pass any kind of authority and do not even pass the link juice to the site and the link is just mentioned on the site or platform. 

These happen on platforms like comments on social media, generating affiliate links, etc. 

Are these links bad? No, these are not bad, they are just natural links so they do not harm your SEO activities. 

How to know if the link is a Do-follow or No-follow?

Just check in the source code. Just right-click and click on inspect. Upon moving your cursor near the link it will be highlighted in the source code and the HTML code mentioned as '=nofollow' or '=dofollow'. 

Conclusion: Well, I have covered everything about the types of links and now managed to clear out all the major doubts about the types of links that can affect the ranking on SERPs.