User.php

<?php

namespace App\Models;

use Fouladgar\OTP\Concerns\HasOTPNotify;
use Fouladgar\OTP\Contracts\OTPNotifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;

class User extends Authenticatable implements OTPNotifiable
{
    use Notifiable;
    use HasOTPNotify;

    // ...
}