Custom page that's create a record

class RequestDomainPage extends Page implements HasForms
{

    use InteractsWithForms;

    protected static ?string $model = RequestDomain::class;
    protected static ?string $navigationIcon = 'heroicon-o-document-text';

    protected static string $view = 'filament.pages.request-domain-page';

    protected static ?string $title = 'Domein aanvragen';


    public $domain;
    public $customer_id;


    public function mount(): void
    {
        $this->form->fill();
    }

    protected function getFormSchema(): array
    {
        return [
          Card::make()->schema([
              TextInput::make('domain')
                  ->label('Domain')
                  ->required(),
              Select::make('customer_id')
                  ->label('Customer')
                  ->placeholder('Select Customer')
                  ->options(
                      \App\Models\Customer::all()->pluck('name', 'id')
                  )
                  ->required(),
          ])
        ];
    }
    protected function getFormActions(): array
    {
        return [
           Action::make('kak')
                    ->label('Submit')
                    ->action(function (RequestDomain $requestDomain) {
                       RequestDomain::create([
                           'domain' => $this->domain,
                           'customer_id' => $this->customer_id
                       ]);
                    }),
        ];
    }
}