After you have successfully installed cPanel & WHM on to your new server, you can activate the license by applying 1 simple command to your server.

You will need to SSH into your server and log into your root account to apply this command

# /usr/local/cpanel/cpkeyclt

Once you have successfully run this command, the server will respond back to let you know that your license was successfully activated.

If you have not yet ordered a cPanel license for your server, you can do this by following this knowledgebase article.

To verify that your license has been registered, you can verify this through the cPanel website
 - https://verify.cpanel.net/