Free Directory submission is a technique to listing your website link to different directories or databases under the exact category or sub category. Ensure to submit your site under the most prefer category to receive the benefit of blog directory submission.
See the free directory submission process in seo:
How To Free Directory Submission in SEO?
Top 100+ free High Page Rank/PR Directory Submission sites list:
High page rank directory submission sites will help to your website link building. Major search engines play a vital role while indexing and crawling.