ldc-crm/app/Http/Requests/Bo/QuestionExport.php

<?php

namespace App\Http\Requests\Bo;

use Illuminate\Foundation\Http\FormRequest;

class QuestionExport extends FormRequest
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return boolean
     */
    public function authorize(): bool
    {
        return auth('backend')->check();
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules(): array
    {
        return [
            'brand' => 'required|numeric|exists:brands,id'
        ];
    }
}