If you want to explore this feature further, you have to associate a custom domain relevant to your product or brand. Let us see more in detail about associating a custom domain and getting it verified before you can start generating smart links.
You can add your domain in Zoho Smart URL and convert your smart links into a customized smart link. Customized smart links are easy for users to recognize and promote your brand and also increase traffic to your links.
From the Navigation toolbar, click Engagement and choose Smart URLs.
Enter your domain and click Associate.
Login to the administrative console of your domain provider.
Navigate to DNS settings.
To point your main domain, add A record and point it to the IP address 136.143.187.52
OR
Once you have updated your domain details, you have to update the DNS settings in your domain registrar and get it verified from Zoho MarketingHub.