Laravel - Notifications - Customizing The Subject

By default, the email's subject is the class name of the notification formatted to "Title Case". So, if your notification class is named InvoicePaid, the email's subject will be Invoice Paid. If you would like to specify a different subject for the message, you may call the subject method when building your message:

     * Get the mail representation of the notification.
     * @param  mixed  $notifiable
     * @return \Illuminate\Notifications\Messages\MailMessage
    public function toMail($notifiable)
        return (new MailMessage)
                    ->subject('Notification Subject')