Twilio
Use Twilio REST API to send SMS
You could for instance send OTP code for authentication
Usage
$client:=Twilio.Client.new("TWILIO_ACCOUNT_SID"; "TWILIO_AUTH_TOKEN")
$message:=New object(\
"body"; "This is the ship that made the Kessel Run in fourteen parsecs?'"; \
"from"; "+15017122661"; \
"to"; "+15558675310")
$client.messages.create($message)
DOC
API Documentation https://www.twilio.com/docs/sms/api
Alterative
Use PHP Execute
, example: https://github.com/jay-jay/4D-Twilio