Governor contact information is usually entered in the Central Register under Non Contracted Personnel (Admin > Personnel > Central Register).
Unfortunately this data does not feed through to the Comms area. For this, you will need to create a staff profile for each Governor you wish to send Comms messages to: Create a New Staff Profile
You will then find their contact details in Admin > Comms, under Staff. To create a Saved Group for Governors, search for each individual so they appear on the right side, and click on the Save Group button. They will then appear under Saved Groups in the Staff part of Comms.
The disadvantage of this approach is that their names will appear in Staff Reports, due to having a Staff Profile (although they won't be included in the Work Force Census). Alternatively you could set up a mailing list outside of ScholarPack using an alternative email carrier. Or, you can copy and paste their email addresses from the Central Register into the Email Directly box when writing an email in Comms, but their details cannot be saved as a Group.