We have an App with Mobile SDK installed. After registration a Contact is created (with an auto-generated Contact Key, since we don't specify one).
We have a input field on the app allowing the user (which is known by a device ID at this stage) allowing our users to add their Email Address.
We use an Attribute added on Mobile Push Attribute Group to send the Email back to MC, fed with the input field above.
How do we transfer this Email Address in Email Studio so that it can be used in a cross channel send (Push + Email) in JB ?
Many thanks in advance for any insight !