Auto signing a user in without user interaction


I am trying to build an app on the BigCommerce marketplace and they require no user interaction when the app is installed or when it is clicked to be loaded again. It seems almost every approach with Auth0 is to have the user signup or login themselves on the Universal Login page, so how can this be done with Auth0?

I have tried to create the user with a random password at the end of the OAuth connection process. This allows me to log the user in the first time since the password is known. But, how can I log the user in again without storing or resetting their password or having them actually login themselves?

Also, it is possible to access our website ( outside of the BigCommerce app and ideally we would like the user to be able to choose and set a password that remains the same. This isn’t possible if the user’s password has to be reset each time in order to log them in. Any ideas on how to solve or work around this problem are much appreciated!