You can do this by running this command in SSH:
/usr/local/cpanel/cpkeyclt
It should look something like this:
[root@cpanel home]# /usr/local/cpanel/cpkeyclt Updating cPanel license...Done. Update succeeded. Building global cache for cpanel...Done [root@cpanel home]#
If you still have questions about activating your cPanel license, make sure to contact us by opening a support ticket or by using our live chat feature.