Understand custom domain in customer portal
The domain is the string that is entered into the address bar and helps identify a source on the internet. An example of domain name is https://www.google.com. By default the customer portal is hosted on the Zoho Creator's domain. The customer portal will be allocated the domain name will be something similar to https://applicationname.zohocreatorportal.com. However, the customer can also host the customer portal on their own domain. This will enable the customer portal to accessible from the organization's own website instead of Zoho creator's.
Let's assume an organization called Zylker uses the Zoho Creator customer portal. Zylker has a domain, www.zylker.com, and wants the customer portal to be available on its own domain instead of the default domain. Zylker can achieve this by using the custom domain feature.
In order to use a custom domain, the domain has to be verified. This is to ensure the linking of the creator customer portal and the domain. The verification of the domain also helps authenticating whether the admin is the real owner of the domain. The verification can be done in three different ways: By adding CNAME, By adding TXT, and By adding file.