We recommend all users to use relative links, when adding URLs to modules. This makes sure that links will keep working regardless of your site’s domain name. For example, this is important if you use several instances (like test/staging and production) and reuse layouts between them.
The relative URL is the part of the URL that comes after the domain (https://help.refined.com/space/CLOUD). For example, adding a navigation icon with a link to the above page looks like this in the layout editor:
