Chargebee provides the option to have a custom domain in the hosted pages and customer portal URL. Also known as white-labeling, this lets you have your brand, instead of Chargebee's on the hosted pages' URLs. This ensures a consistent customer experience.
Say, the URL of your current checkout page reads yourcompany.chargebee.com.
With the Custom Domain feature enabled, you can have a URL that reads billing.yourcompany.com.