When users subscribe to daily update, they receive a push notification each day that they can tap to invoke one of your intents configured as a daily update. You can prompt for daily update subscription either mid-conversation or as a suggestion chip when the user exits your Action successfully.
Provide users with enough context to understand the benefit of your daily updates before requesting that they register for them. If your daily updates only have the same content every day, users will probably unsubscribe after a few days. To prevent this, keep the conversation short after your daily update intent triggers, and only offer a daily updates subscription when it makes sense to do so.