How do I enable SPF/DKIM for all accounts on the server?
An individual account can have SPF/DKIM created by going to the Email Deliverability page in that account's cPanel interface and clicking the buttons to install the suggested record.
However, if you have many accounts on the server that do not have these records, that is prohibitively time-consuming.
You may enable or disable SPF/DKIM for every domain on the server at "WHM Home »DNS Functions »Enable DKIM/SPF Globally."
You may read our documentation on this feature here.