hi all noob scouring android forums for help/idea on how to execute an app idea

thank you for taking the time to read in advance. I am currently a student trying to build an app for my final project. I want to build an app for rideshare drivers to download to provide a 'service' per se to the riders. I don't want to have the riders need to download the app as they will only be in the ride for a short time, but somehow send a request to the driver(via text or someway). herein lies the issue. I don't want it to be necessary for the driver to give out his personal phone number to accomplish this. I originally thought of a shortcode to text to but the more research I do into that it may not be possible not 100% sure on that though. anyway, I was just wondering if anyone has some sort of ideas on how to implement this type of app and keep drivers privacy in mind. again thanks for reading and open to all ideas thank you

it is not a ridesharing app it self it is more like an app that does like say song requests. where they can type in via text the name of the song and when the drivers phone gets the text the app reads it and plays the song. thank you sorry if I was not clear