HI,
SEO is part of online advertising. If you want to promote your website or business online you can choose SEO.
Because it will provide strong and long result. SEO is the best path for your business development in online.
It will stand for three types: 1. White Hat SEO, 2. Black Hat SEO, 3. Grey Hat SEO.
Google and major search engines suggest doing White hat SEO.
SEO divided into two subcategories: 1. On-Page SEO, 2. Off-Page SEO
On-Page SEO: You can do all the activities into the website or web page like meta tags optimization, Google Analytics and search console code optimization, xml sitemap, robots txt optimization, ect...
Off-Page SEO: You can do all the external activities like Search engine submission, Business directory submission, Blog content optimization, Blog commenting, article posting, forum discussion, Image, and Video optimization, ect...