Prerequisites       

1. Organization Owner
   
2. Organization Admin

1. Permission to update your domain's DNS records in your domain registrar's Domain Manager.

Overview

1. Add users with custom domain-based email addresses
   
2. Create mailboxes for users
   
3. Add domain-based aliases for users

Steps to add and verify a domain

1. Sign in to Zoho One, then click Directory in the left menu.
   
2. Go to Domains, then click Add Domain.
   
      
   
   
3. Enter the domain name, then click Add.
   
      
   
   
4. Follow the displayed instructions to finish setting up your domain by adding a TXT record in your domain host. (For example: GoDaddy, Cloudflare, Namecheap, Google Domains, etc.,)
   
      
   
   
5. Steps for TXT record verification:
   
1. Sign in to your domain hosting site and open your Domain Management page to update the DNS records.
   
2. Locate the option to add a new record.
   
3. To add a TXT record:
   
1. In the Type field, select TXT.
   
2. In the Name field, enter '@' or leave it blank.
   Note: If you are verifying a subdomain, enter the subdomain name. For example, the host name for "zo.zylker.com"will be "zo".
3. In the Value field, copy the corresponding TXT record value from Zoho One and paste it here.
   
4. In the TTL field, set the minimum possible value recommended by your domain host.
   
4. Wait for an hour or two so the values can propagate.
   
5. Return to the Verify Domain screen in Zoho One, then click Verify.

Note: If you face any issue performing the steps in your domain host, consult their help documents or their support  team.