As we know that CURL is a library that allow us to make requests(HTTP requests) in PHP.

We can upload a file as well using CURL. For upload a file using CURL must follow below points :

1. Uploading file size is mandatory to be less than file allowed by the Server.

2. If file size is too big , then it may take a bit more time.

3. Please replace "uploadFile.zip" named file with the file which you want for uploading. and it should addressed with full path.

4. replace "http://localhost/test/index2" with that URL for which server has given the functionality for upload file.

    $file_name_with_full_path = realpath('uploadFile.zip');        
    $url = "http://localhost/test/index2";
    $post_data = array(
                "foo" => "bar",
                  "upload" => "@".$file_name_with_full_path
              );
     try {
         $ch = curl_init();
         curl_setopt($ch, CURLOPT_URL, $url);
         curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
         curl_setopt($ch, CURLOPT_POST, 1);
         curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
         $output = curl_exec($ch);
         curl_close($ch);
   } catch (Exception $e) {
            echo $e->getMessage();
            die;
   }