Does Zorin Pro has any validation that needs a licence key?

[ZorinLover]

Thank you replying.
And sorry, but there's still a question that I would like to know: Is any licence key sent by email that needs to be entered in the installation wizard?

Update:
Mmm seems that there's no licence key, at least in Zorin OS 16, so no problem if installing it in a system without active internet connection then?

Where to key in registration number after install?

There is no "license" or registration number. However, your client may need support directly from ZorinGroup at a later date. So, this is a recommendation as they would need to show their Zorin OS Pro receipt or use their purchase Download Email to contact support. As far as Distributing goes, I would recommend you use your Zorin Pro Contact Forum to ask the developers @AZorin and @zorink directly to ensure legal compliance.