Enable Akismet plugin

Akismet plugin is so important to protect your WordPress installation, if you allow the comment.

Akismet, or Automattic Kismet, is a spam filtering service created by Automattic, the corporation which employs most of the main developers of the weblog platform WordPress. Akismet attempts to filter link spam from blog comments and spam TrackBack pings. The filter works by combining information about spam captured on all participating blogs, and then using those spam rules to block future spam.
Above description from Wiki

I need a WordPress.com account to ge the API key. It is free to get it.

Akismet is already included in the WordPress package. I just need to activate it and put the API key. Done