High-quality, relevant content is the cornerstone of On-Page SEO while external links and social signals are the essential ingredients in Off-Page SEO.
Keywords are used in content and meta-tags for on-page SEO whereas keyword enriched anchor texts are developed in backlinking for off-page SEO.
Site speed and user experience are enhanced by On-Page SEO while off-page SEO has no direct bearing on website performance.
Link building is not part of On-Page SEO, instead it focuses on generating outside backlinks.
For the on-page, it entails site structure and HTML, while off-page is concerned with online presence off-site.
You have full control over On-Page SEO; Off-Page SEO is dictated by external partners and customers’ opinions.
While the on-page SEO will give more or less immediate results, off-page SEO will not see the fruits of its labor so soon.