سلام دوست عزیز

طبق دایکیومنت لاراول توی AuthServiceProvider قرار دادید؟

https://laravel.com/docs/9.x/verification#customization

use Illuminate\\Auth\\Notifications\\VerifyEmail;
use Illuminate\\Notifications\\Messages\\MailMessage;
 
/**
 * Register any authentication / authorization services.
 *
 * @return void
 */
public function boot()
{
    // ...
 
    VerifyEmail::toMailUsing(function ($notifiable, $url) {
        return (new MailMessage)
            ->subject('Verify Email Address')
            ->line('Click the button below to verify your email address.')
            ->action('Verify Email Address', $url);
    });
}