youtube-download-service/app/Http/Controllers/DownloadController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class DownloadController extends Controller
{
    public function download($file_name) {
        $file_path = public_path('/'.'downloads/'.$file_name);
        $headers = [
            'Content-Type' => 'video/mp4',
        ];
        return response()->download($file_path, $file_name, $headers);
    }
}