Which is the best way to learn SEO from scratch?
udemy.com is the way to Learning Search Engine Optimization (SEO) from Scratch.
SEO: The Beginner's Guide to Search Engine Optimization from
Moz is a great resource to start with. It starts from the very basic of SEO and enables you for further understanding of an always changing field of SEO.
There are lot of online certification websites like acadmic earth, udemy, coursera we an learn seo from this sites the best.