To start sending emails in the Email Marketing section, you need to first connect your domain. You can do that in the Emails & Automation section -> Settings.
There you have the option to add your domain. After adding the domain to the platform, all you need to do is add the CNAME and TXT records provided to you.
Simply go to the domain settings where you’ve purchased the domain and find the DNS Records area to add the CNAME and TXT records. It might take some time for the DNS records to update after adding them, so don’t worry. Check again in 10-15 minutes, and in most cases, it should start showing as ‘Verified‘ in green.