Bus booking app Message (sms)

I am making bus booking app.
How can I inform user or customer his or her ticket was booked on sms or on WhatsApp
Any solution for this question please help me .

i think for that you have to use any sms service api, which maybe not free, and for whatsapp you need a verify business account and then connect that to your app, which is not easily approved for everyone, and also i dont think so Kodular can attach whats app account with your app, you can try to search some sms service and then get there api, to send sms

like this tutorial , as he is setting otp sms you can send your own sms