Hi,
As far as I know, you cannot edit the standard email from Morpheus - therefore you find a request within the “Idea” section of this discuss forum - perhaps you would like to vote for it:
In case you want to send out your own emails only, you need to create an email task for that and stop the standard email within the user settings by unchecking the “receive notifications”.
Perhaps the vote runs thru successfully with enough votes …
Hope this helps already!