Technical SEO is where a website’s infrastructure is optimized so the search engine can crawl and index it without encountering any errors. Most search engines have robots (known as crawlers) which discover digital pages with the help of crawlers, search engines then index the website on its web pages. Technical SEO enhances the process of crawling and indexing, hence, ranking the website higher than others.
On-Page SEO is the process of optimizing specific pages by adding relevant keywords, bold & clear headings, and good user experience so the page also can be ranked higher.
Off-Page SEO is the SEO done outside the website, like social media marketing. It marks the website’s reputation. Primary examples are backlinks from a reputed sites.