SEO(Search engine optimization) is the process of optimizing your website for the purpose of getting free traffic from search engines. An optimized website is more easily understood by Search engine crawlers. This increases the chances of ranking higher in SERPS(Search Engine Results Page).
There are two types of SEO Activity
On Page Activity
On Page Activity: On Page means All Activities you perform on your website to assist you to rank higher, for instance, Meta Tags, Meta Keywords, Meta Descriptions, Page Titles, Internal Linking, Title Tags of Hyperlinks, Alt Tags for IMG etc. Still you need to keep in mind few Factors while doing on page Optimization.