Creating applications in Personio and send File

Hey I try to Send a File in PHP with CURL and I do not really get how to do it.

I uploaded the file to then send it via API Persoio.
What does the UUID stand for. I do not get such an Value when I upload a file!?

Can someone help?

        'files' => [
          [
            'category' => 'cv',
            'uuid' => XXXX
            'original_filename' => $_FILES['fileInput']['name']
          ]
        ]