Off-Page SEO is essentially any work you or your SEO agency does outside of your website so as to improve the SEO on your website. The name off-page SEO has always confused me since to me “off-page” could mean on the webserver, other webpages on the same website, etc. But that is NOT the case. Off-Page SEO is work done outside of your website. I prefer to call it off-site SEO. 😉
Here are some examples of Off-Page SEO:
Brand building
Link building
Citation building
Social Media
Google Business Profile (aka: GMB)
Bing Places
Here are a couple links that have more details about off-page SEO:
Off-Page SEO Ranking Factors [2021] – Moz
What Is Off-Page SEO? A Comprehensive Guide (semrush.com)