Can I use fabrics Digits just to verify my app's users mobile number?I don't need to sign in user based on that. Is there any sample app code available ?
you can... although i would recommend against it at this point. Due to google acquiring fabric it is likely that they might discontinue digits(this is the current speculation).
Check out msg91 and their sendotp feature. I am myself planning to use that. As for sample code, google it and you'll find tonnes of examples
P.s there are other otp verification providers as well eg 2factor authentication, nexmo,twillio etc