Many commercial ioT devices now come with a setup proceedure that consists of:

1. A setup App on the phone that uses bluetooth to connect to the device.
2. The user enters the ssid and password of the router that the device will connect to for ongoing communication to the web.
3. The device, in my case ESP32, will then save the SSID and password for all future communications. 
4. Bluetooth connection is ended with the phone app and all further communication is through the Wifi using the SSID saved on the device.

Before diving into writing my own app for such a purpose, I believe there must be a library out there that does this already. It would include the ESP32 C++ code and also the Apple/Android App. I don’t know what search term to use for a google  search but does anyone know of a popular library?