elementary provides badges, e.g. for your GitHub README. Badges will open to your app's page on the AppCenter website where users can learn more about your app, see screenshots, and decide to download it. They look like this:
Markdown
[](https://appcenter.elementary.io/io.github.USER.REPO)
HTML
<a href="https://appcenter.elementary.io/io.github.USER.REPO"><img src="https://appcenter.elementary.io/badge.svg" alt="Get it on AppCenter"></a>
Make sure to replace io.github.USER.REPO in the URL with the ID for your app