International SEO helps you rank your website for a particular country, by optimising your site so that search engines can identify the country(ies) you are targeting.
This is achieved through the use of preferred keywords in multiple languages.
The challenge is that International SEO also requires you to have content that is relevant for users in different targeted time zones and areas, who are using several currencies and languages. Ideally, you should tailor the content for each region separately, which is not always a walk in the park, especially if you lack the necessary resources.
Another big issue in International SEO is duplicate content that can negatively affect your SEO campaign.