There are many buyers and sellers who don't know how to identify a do-follow link. It is very easy to identify the link attribute. Do-follow backlinks are simple hyperlinks on a webpage. There are some sites where people usually share different types of links. And the website owner doesn't want to pass the link juice to all those low-quality web pages.
I did not Know About It a year ago. May be there are many people like me.
Google allows us to use no-follow attribute which has no direct SEO value. It can help you indirectly. We always want to build do-follow links because it adds link juice+visitors. When someone put no-follow attributes to a link <a href="link" rel="nofollow">Text</a> this type of links are no-follow. All other links are do-follow.
Example: This community discussion on Seoclerks uses no-follow attributes(probably) to outbound links. Here is an anchor- Blogging and SEO Tips . I have used the link here with anchor "Blogging ad SEO Tips". Press the right button on the mouse. And then press the inspect element.
CTRL+F from keyboard to get the search field. And then type the link bloggingnseo.xyz and see. Is there nofollow attribute beside it. If so, it is a nofollow link. If you don't see anything like that. It will be a do-follow link.
Links inside popular and high DA websites- Medium, Linkedin, Evernote, Quora, wn.com, and lot more sites use nofollow attributes. It will never add link juice but visitors. This type of SEO is known as parasite SEO. It will not increase your webpage rank on Google.
If You are a buyer and you don't know this, you may be cheated sometimes by sellers. If you are a seller, it will help you to do SEO perfectly. I guess most of the Seoclerks users know this. Thanks for reading.