How do I enable/setup/turn on encryption for all Domains in our G Suite account?

Follow these steps to turn on encryption for all Domains in your G Suite account:

Go to “Tools”→“Google Drive Encryption”→“Encryption App Settings.” You will see the domains listed under this section. Here, you can switch encryption ON/OFF for the domains.

You can enable/disable encryption at the user-level by clicking on the drop-down beside the domain name and selecting from the list of users in the domain.