How to integrate SMS API in WordPress WooCommerce?

To integrate an SMS API in WordPress WooCommerce, first choose an SMS provider (Twilio, MSG91, Textlocal, Plivo, etc.) and get API keys, sender ID, and templates. The easiest method is a plugin. Install an SMS plugin that supports WooCommerce events like new order, processing, completed, failed, and OTP. Add your API credentials in the plugin settings and map templates for customer and admin messages. If you prefer custom code, use WooCommerce hooks like woocommerce_order_status_changed to trigger an API request with order data (name, order ID, amount). Test in sandbox, verify delivery reports, then enable live mode.