create_customer.php

<?php
/*
Author:Minhazul Min
Website: https://minhazulmin.github.io/
 */

require_once 'stripe_header.php';

$payment_intent_id = !empty( $jsonObj->payment_intent_id ) ? $jsonObj->payment_intent_id : '';
$fullname          = !empty( $jsonObj->fullname ) ? $jsonObj->fullname : '';
$email             = !empty( $jsonObj->email ) ? $jsonObj->email : '';

// Add new customer fullname and email to stripe
try {
    $customer = \Stripe\Customer::create( [
        'name'  => $fullname,
        'email' => $email,
    ] );
} catch ( Exception $e ) {
    $error = $e->getMessage();
}

if ( empty( $error ) && !empty( $customer ) ) {
    try {
        // Attach Customer Data with PaymentIntent using customer ID
        \Stripe\PaymentIntent::update( $payment_intent_id, [
            'customer' => $customer->id,
        ] );
    } catch ( Exception $e ) {
        $error = $e->getMessage();
    }
    $output = [
        'customer_id' => $customer->id,
    ];
    echo json_encode( $output );

} else {
    http_response_code( 500 );
    echo json_encode( ['error' => $error] );
}
?>