You can view/edit the email ids with the following steps:
1. Click the gear icon in the upper right corner and select account settings
2. Select notification settings.
For more info on the custom alerts, please visit: https://support.google.com/adwords/answer/1704338?hl=en
Hope this helps!
just go to Bulk Operations on the left hand vertical menu and go to Automated Rules - you can see emails for any rule created within this AdWords account. You cannot change emails for existing rules. Email is automatically set the same as your login to AdWords.