Search engine optimization is the key of digital marketing,only unpaid way for making your website rank in top of google page results.
There are three types of doing search engine optimization
1 white hat seo
It is done by strictly following google webmaster guidelines .it is the suggested and best way of doing SEO
2 Grey hat SEO
It is done by overdoing the guidelines of google webmaster guidelines
3 Black hat SEO
It is completely against google webmaster guidelines. And will be banned within a short time when google finds out.
Seo is again divided based on the way of optimizing
It will be teached in the next blog