how to add custom functionality after woocommerce place order button

Question

I am creating a plugin to send a one time password (OTP) to the user when the place order button is clicked. When the user clicks the button, the number from the phone number field must be captured and an API must be called to send the OTP. After that, a page with an input text box to enter the OTP must be present. If the user doesn't verify the order with the OTP, it must not be placed.

I am unable to find any hook to place such a textbox area and for the order placing.

Answer 1

You can use woocommerce_after_checkout_validation for custom validation. Following snippet might be helpful for you.

//Action to validate
add_action('woocommerce_after_checkout_validation', 'after_checkout_otp_validation');

//The function
function after_checkout_otp_validation( $posted ) {

    // you can use wc_add_notice with a second parameter as "error" to stop the order from being placed
    if (error) {
         wc_add_notice( __( "Incorrect OTP!", 'text-domain' ), 'error' );
    }

}