Some domains aren't recognized as clickable links on Apple devices unless they include the full URL with https:// or http://. Include the full URL when sharing your links to ensure your links are clickable.
We contacted Apple and learned that "less familiar or new top-level domains aren't recognized as clickable links on Apple devices primarily due to Apple's security and formatting rules. To ensure a domain is recognized as a link, it must include the full URL schema (https:// or http://)."
An unofficial list is maintained at https://recognized.link/.
Examples of domains typed into Apple Notes: