Yes, the latest version of Comic Life 3 is compatible with macOS Mojave (10.14).
If you purchased from the Mac App Store, then update using the Mac App Store.
If you purchased from plasq.com, please download the latest Comic Life 3 version from here: http://plasq.com/downloads/
Click the orange "For Mac Desktop Download" button, and it will download to your Downloads folder. You then need to move it to your Applications folder. (Replace the current version you have with this new version).
It will detect your previous registration information (unless you reinstalled macOS from scratch).
If it does say it needs to be registered, and you don't have your registration details, find out how to retrieve it here.
If you have any issues, be sure to contact us directly.