Certified/app/Notifications/CertificateExpiringNotification.php

<?php

namespace App\Notifications;

use App\Models\Certificate;
use App\Models\User;
use Illuminate\Bus\Queueable;
use Illuminate\Notifications\Messages\MailMessage;
use Illuminate\Notifications\Notification;

class CertificateExpiringNotification extends Notification
{
    use Queueable;

    public function __construct(public Certificate $certificate) {}

    /**
     * @return array<int, string>
     */
    public function via(object $notifiable): array
    {
        return ['mail'];
    }

    public function toMail(User $notifiable): MailMessage
    {
        $date = $this->certificate->expires_at->toFormattedDateString();

        return (new MailMessage)
            ->subject(__('Certificate expiring soon: :title', ['title' => $this->certificate->title]))
            ->greeting(__('Hello :name,', ['name' => $notifiable->name]))
            ->line(__('Your certificate ":title" will expire on :date.', [
                'title' => $this->certificate->title,
                'date' => $date,
            ]))
            ->action(__('View your certificates'), route('certificates.index'))
            ->line(__('Please renew it in good time to stay compliant.'));
    }
}