Yes, Email Notification can be disabled / turned off in Adobe Sign.
Email Notification Like: Please Sign email, Signed & Filed to the Signers and so on.
Note: Contact support to get the email notifications disabled.
The other "Notification" emails can be turned off from Personal Preferences of each user.
https://helpx.adobe.com/sign/help/quick-setup-guide.html |"Configure personal events/alerts"