There is a distinction to make here as there are Users (alarm panel users and Alarm.com notification contacts) and Logins (login credentials for Alarm.com website and app)
It sounds like you want to create a Login for your wife but have described adding a panel user. See the steps to create a Login below:
You’ll be able to adjust permissions individually or just give master control to the new login which will give basically all the same abilities as your primary login credentials.