How can I add forum plug-in in my WordPress blog?

Know how you add a Forum section in your WordPress blog. See which plugin can do this and how to do it.

I run my own blog named mechanicalduniya with a .com domain. I want my viewers to exchange their views during the visit. So, I want to add a forum section to my website. How can I add a forum section? What are the options available nowadays from available plugins?