Hi @navin_displayride ,
In general you can find the email notification options on the Settings tab of your app on bitrise.io
You can configure that you want to receive emails for every failed build, and no email at all for successful builds. You can’t limit that for a workflow / nightly build though.
If that wouldn’t be enough for your use case then I’d suggest you to turn those off and instead add an email step to the workflow(s) and configure that any way you like. E.g. our Send Email with Mailgun step should be flexible enough.
If you’d have any questions just let us know!