The Smart TV approach — If you are a cord cutter, you’ve probably seen a message like this: “To activate HBO Go on this device, go to hbogo.com/active on your mobile device and enter the Activation Code KP2428”. You could use a similar approach to allow users to access temporary, but personalized pages, triggered by certain events in your voice application. This may be helpful if you don’t want to implement an authorization layer in your account, but may sometimes need a visual web interface with dynamic content.
Ask for a phone number or email address — Grab a user’s phone or email once, store this information, and send links using sms or email with your own messaging service or something like Twilio. You can also offer account-linking with something like Gmail and request permission to a user’s email in this way.
Multi-modal interace — Our friends over at Pylon built a great app called Tasted that lets users work through a cooking recipe using their Alexa app, which drives the experience hands-free on the companion iPad app. With a native iPhone or Android app, your backend voice application can talk with your tablet and phone app and push notifications all day long! You could also do something similar with standard web app (no native phone app). Within the Alexa conversation, simply instruct the user to access their account on your website when the need arises.