On-Page SEO covers everything you control directly on your website: quality content matching what people search for, proper use of headings, optimized page titles and meta descriptions, image alt text, internal linking, and fast page speed. Off-Page SEO covers factors outside your website that build authority: backlinks from other reputable websites, Google Business Profile optimization, social media presence, and online reviews. Both work together — great on-page content with zero off-page authority rarely ranks well, and strong backlinks can't compensate for thin or irrelevant page content.