You can follow the below steps to add the domain in your EMM panel

1) Login to your EMM panel

2) Click on Admin->Account Configuration

3) Click on Add under Domain Name for Sending Email Broadcast

4) Click on Add New and enter the domain that you would like to add and Click on Check

NOTE: The domain should have an A record to it.

5) Click on Verify

6) Choose By DNS Record and Click on Proceed.

7) Update the given DNS in your Domain Cpanel and Click on Close

8) Now click on Authenticate for the same domain

9)Choose Select By Both (optional) and Click on Proceed

10) Update the given DNS in your domain Cpanel and Click on Close

11) Once the DNS settings are reflect globally the domain will be Ready For Use.