SEO stands for Search Engine Optimisation. This is where you construct your web pages and implement certain techniques to help you rank as high as possible on search engine result pages (SERPs). The higher your pages can rank on Google/Bing/Yahoo/etc. results pages, the more traffic your site is likely to get. , It split up into two categories as On-Page SEO and Off-Page SEO.
On-Page SEO :
Onpage optimization refers to all measures that can be taken directly within the website in order to improve its position in the search rankings. On-page SEO some important activits are Page Titles ,Meta Descriptions,Meta Tags,URL Structure,Body Tags (H1, H2, H3, H4, etc.),Keyword Density,Image alt and tittle tag, Internal Linking and Website content
Off-Page SEO :
Off page optimiztion refers to all measures that can be taken out side the website in order to create the traffic to words website . Off-page SEO activits are networking, article submission, forum & blog marketing, backlink creation etc