How to transfer to the user the data that he sent?

Question

ASP.NET

There are two services, apishka and smtp. Appointment for the purchase of some goods. When the user makes a purchase, he should receive an email that he ordered.

Endpoint for sending a purchase:

[HttpPost]
        public async Task<IActionResult> Add(OrderCreateModel orderModel)
        {
            var orderAdd = _mapper.Map<OrderDto>(orderModel);
            var orderCreated = await _orderService.AddAsync(orderAdd);

            _messageService.Enqueue(orderCreated);
            return CreatedAtAction(nameof(GetId), new { id = orderCreated.Id }, orderModel);
        }

And this is how my SMTP service is triggered when an order arrives:

public Task StartAsync(CancellationToken cancellationToken)
        {
            var factory = new ConnectionFactory()
            {
                HostName = _rabbitSettings.Value.HostName,
                UserName = _rabbitSettings.Value.UserName,
                Password = _rabbitSettings.Value.Password,
                Port = _rabbitSettings.Value.Port,
                VirtualHost = _rabbitSettings.Value.VirtualHost,
                AutomaticRecoveryEnabled = _rabbitSettings.Value.AutomaticRecoveryEnabled
            };

            IConnection connection = factory.CreateConnection();
            IModel model = connection.CreateModel();

            model.QueueDeclare(queue: "order",
                        durable: false,
                        exclusive: false,
                        autoDelete: false,
                        arguments: null);

            var consumer = new EventingBasicConsumer(model);

            consumer.Received += async (sender, e) =>
            {
                var body = Deserialize<Mail>(e.Body.ToArray());
                await _mailService.SendMessageAsync(body);
            };
            
            model.BasicConsume("order", true, consumer);

            return Task.CompletedTask;
        }

Which calls the service already on dispatch:

public async Task SendMessageAsync(Mail mail)
        {
            var email = new MimeMessage();
            email.Sender = MailboxAddress.Parse(_mailSettings.Value.Mail);
            email.To.Add(MailboxAddress.Parse(mail.Email));
            email.Subject = mail.Subject;

            var builder = new BodyBuilder();
            builder.HtmlBody = mail.Body;
            email.Body = builder.ToMessageBody();

            using var smtp = new SmtpClient();
            smtp.Connect(_mailSettings.Value.Host, _mailSettings.Value.Port, SecureSocketOptions.StartTls);
            smtp.Authenticate(_mailSettings.Value.Mail, _mailSettings.Value.Password);

            await smtp.SendAsync(email);
            smtp.Disconnect(true);
        }

And here is this hardcoded model:

public class Mail
    {
        public string Email { get; set; } = "[email protected]";
        public string Subject { get; set; } = "Greetings!";
        public string Body { get; set; } = "Greetings!";
    }

Now the question is how do I send a letter that arrived from Rabbit (purchase of goods that occurred on the API endpoint)