Google, Bing and Yahoo are the most popular search engine in the world. When you search something on google it brings you so many results and so many websites. SEO (Search Engine Optimization) is the process to increase the quality and quantity traffic of you website through search engine results or it's the process of getting traffic from the free, organic, editorial or natural search results on search engines. SEO helps you to make your website on the top of the search engine page. SEO helps you to make your websites on the top of the search engine page for example on google from that you can bring so many traffic on your  websites and you could be popular in few times. There are mainly three types of SEO they are Black hat seo, White hat seo and Gray hat seo.

White Hat SEO 

In search engine optimization white hat SEO refers to the usage of Optimization techniques and tactics that focus on a human audience . Mainly White Hat SEO includes Keywords, backlinking and best content for readers.  John Andrews  explains I like to refer to White Hat SEO is as “conservatives” of the SEO world… where things are viewed as BLACK or WHITE (GOOD or BAD), and the letter of the Google god is taken verbatim as TRUTH. Yes, there is a bit of a timeline problem with that approach but that’s just the tip of the White Hat iceberg.

Black Hat SEO 

 In search engine optimization black hat SEO refers to the use of competitive SEO techniques and tactics. Black Hat SEO  includes keyword, invisible text, doorway pages etc. Black Hat SEO is not focus on a human audience. SEO Consultant John Andrews  explains techniques or tactics which have been defined by Google as in violation of the Google “Quality Guidelines” (see “Quality Guidelines, which outline some of the illicit practices that may lead to a site being removed entirely from the Google index”) . Google says anything that strongly suggests Google took action against a site for some specific reason. Black Hat SEO is know what they are doing is defined as BAD, and do it anyway for specific reasons (not usually including “get banned”). I like to think of Black Hat SEO is as opportunists.

Gray Hat SEO 

Gray hat SEO its title proves, is a little black and little white. But it’s note.It’s neither belong to black hat seo nor white hat seo.  It’s more riskier that White Hat SEO. John Andrews explains Gray Hat SEO is not something between Black Hat and White Hat, but rather "the practice of tactics/techniques which remain ill-defined by published material coming out of Google, and for which reasonable people would disagree on how the tactics support or contrast with the spirit of Google’s published guidelines."