Hreflang tags specify to Google that each duplicate content piece targets a different language and country.
This is important since you may want specific users to interact with a certain section of your website. For example, the UK English-speaking version may have unique content, CTAs, and web elements only for that country. Otherwise, Google may show a different version of that same content, meaning the wrong audience lands on the wrong part of your site.Unfortunately, you cannot target by region (EMEA, APAC…), only by language and country. You also need a default version for all languages, a default main language version, self-referencing tags, and the same tags across duplicate content. Hreflang tags are somewhat tedious yet foundational for international SEO.