How do blog links affect on SEO?

I totally agree with the answer of MR. Haseeb Khalid that LINKS PLAYS AN INTEGRAL ROLE IN SEO.

I have learned some right stuff here. I really like your articles.  

The purpose of links is to connect your web site to others that are relevant to the information included on your site. In addition, links provide a method by which traffic to your site is increased, and that is the reason why you are doing SEO. Your desire is to increase the traffic to your site, which in turn increases the number of products that you sell, or the number of appointments that you set with highly qualified clients. In short, links lead to increased profit and growth.Another reason links are so important is that links into your site from other web sites serve as votes for the value of your site. Usually, the more links that lead to your site, the more weight a search engine crawler will give the site, which in turn equates to a better search engine ranking, especially for search engines such as Google that use a quality ranking factor such as PageRank

Links are important in SEO, links to higher page rank sites can bring more traffic and visibility in search. Google’s ranking algorithm  heavily dependent on quality hyperlinks .