On-page SEO refers to how you can optimize your individual web pages or posts on your website to improve the search engine rankings of these optimized individual pages on SERP(search engine results page). On-site SEO refers to the optimization stuff that you do on your website to make sure that your website’s home page is ranked good across all the search engines.
Off-page SEO refers to the techniques that improve the rankings of your individual posts or web pages on SERP(search engine results page). Off-site SEO refers to the techniques that improve the rankings of your website’s home page all across the search engines with your main focus to be on Google.
Title
Meta Description
H1, H2, H3, H4 Tags
Bold, Italic, and Underline the keyword.
Image ALT Text.
Keyword Density
Internal Linking
URL Structure
LSI Keywords
Responsive Website or Blog
Site Speed
Post Length
The number of linking domains
The number of linking pages
Pagerank of linking page
Link relevancy
Authority of linking domain
Links from homepage
Number of dofollow vs. nofollow links
Diversity of link types
Contextual links
Link archor
Citations