FLStudio program from inside FLStudio. Enter your sign in email and password into the FLStudio Help > About window. registration instructions (Windows & macOS)
Use FLStudio. Next time you open FLStudio you should find that ...
Essentially, I don't know how to change the plugins I bought from trial version to the full versions. I bought the Signature Bundle and a few of the plugins/VST changed from their trial versions to the actual full version ...