Article Submission is an SEO technique that involves writing skills. Article submission is the relaying of informational articles and putting a link going to the site or page that you are optimizing.
For example, your website is about search engine optimization. You can write a 250-350 article about SEO definition and put a link back to your site. You can submit your article to various article submission sites like ezine articles.
Article writing is an effective way of promoting your website and to increase your online visibility.