A few lines of code. Every network.

# Illustrative request. Your endpoint and API key are in your dashboard
curl -X POST "$TO_API_ENDPOINT" \
  -d "api_key=$TO_API_KEY" \
  -d "sender_id=YOURBRAND" \
  -d "to=94771234567" \
  -d "message=Your OTP is 482913"

// Illustrative request. See your dashboard for exact parameters
$payload = [
  'api_key'   => getenv('TO_API_KEY'),
  'sender_id' => 'YOURBRAND',
  'to'        => '94771234567',
  'message'   => 'Your OTP is 482913',
];
$ch = curl_init(getenv('TO_API_ENDPOINT'));
curl_setopt_array($ch, [CURLOPT_POST => true, CURLOPT_POSTFIELDS => $payload, CURLOPT_RETURNTRANSFER => true]);
echo curl_exec($ch);

// Illustrative request. See your dashboard for exact parameters
const res = await fetch(process.env.TO_API_ENDPOINT, {
  method: "POST",
  body: new URLSearchParams({
    api_key: process.env.TO_API_KEY,
    sender_id: "YOURBRAND",
    to: "94771234567",
    message: "Your OTP is 482913",
  }),
});
console.log(await res.text());