Cloud programs do not use a serial number, they are activated when you log in to your paid Cloud account
Cloud Getting Started https://helpx.adobe.com/creative-cloud/topics/getting-started.html
okay, but had downloaded a trial version and now I bought the monthly service, when I try to open my project appears to fill the serial number.
Can you help me?
Un-install the trial, run the cleaner, and install the paid version
-using the cleaner after uninstalling and before reinstalling will usually help