Search Engine Optimization is a practice of optimizing websites to improve its visibility & rankings in SERP.
On-page refers to optimizing a webpage's content & HTML elements, whereas Off-page involves building external signals like backlinks.
Meta tags provide information about a web page such as title, description & keywords to search engines.
Keyword research is the process of identifying the search terms & phrases people use to find information online.
Backlinks are links from external websites that point to your website. They are important because search engines view them as a vote.
Mobile SEO involves optimizing websites for mobile users, considering factors like responsive, mobile-friendly & page speeds.