Yes! Even as a cloud user you can use your own subdomain. This allows Zammad to be better integrated into your own environment.
In order to use a subdomain you'll need to create a new subdomain within your DNS. This subdomain needs to be a CNAME with the URL of your instance (for exmaple yourname.zammad.com). As soon as you have configured your subdomain, please send us a short email to email@example.com to tell us your subdomain and instance name.
Please note that proxied CNAME records like with cloudfare are not supported.
If you don't want to use a let's encrypt certificate, you can also use your own certificate (which can be publicly verified, RSA keys required) . To do so we'll need your certificate file and its private key.
When we finished our work, we'll give you a short notice that you're ready to go. From that moment on you can use your own subdomain with Zammad. Also, the instance will now communicate your subdomain as its own URL.