SiteToDo/services/registration.php

<?php 
require $_SERVER['DOCUMENT_ROOT'].'/services/connect.php'; //Подключение connect.php
$_POST = json_decode(file_get_contents('php://input'), true);
//Пост запрос к БД на вставку
$name = $_POST["name"];
$surname = $_POST["surname"];
$address = $_POST["address"];
$email = $_POST["email"];
$password = $_POST["password"];

//Хешируем пароль, чтобы безопасно сохранить
$hash = password_hash($password, PASSWORD_DEFAULT);

$query = "INSERT INTO users (`name`, `surname`, `address`, `email`, `password`) VALUES ('$name', '$surname', '$address', '$email', '$hash')";

$result = $mysql->query($query);

if(!$result){
    echo "Произошли неполадки при регистрации: ". $mysql->error;
}

//Response

$query = "SELECT * FROM users WHERE `email` = '$email'";
$result = $mysql->query($query);

if(!$result){
    echo "Произошли неполадки при получении email: ". $mysql->error;
}

$id = $result->fetch_assoc()["id"];

$data = [
    "id" => $id,
    "name" => $name,
    "surname" => $surname,
    "address" => $address,
    "email" => $email,
    "result" => true
];

header('Content-Type: application/json;charset=utf-8');
echo json_encode($data);