seo means marketing yoiur site on internet by giving your site links and signatures in ,profile, bookmark, blog, article etc it will give u result with your keyword search result. to find your keywords result do use google and u will find the keywords page rank.
more seo more chance to come on first in google.
that is seo that u can do it for your own or u can go to any seo service provider company they will charge u and give u better result.

SEO requirements
1> Depend on your knowledge
2> Unique writing skill
3> Different content writing
and Etc

Also a god SEO person must be always informed of what the competition is doing and how things are evolving for search engines

key word promoter called seo.

Basically it's to improve SERP.

Ability to bring organic result by doing on page and off page.

Improve SERP using SEO off page and on page tactics.