I want to check if the pdf document is readonly more specifically whether the user can modify it by adding signature.

When viewing the document's security properties we can see the value "Signing: Not Allowed".

I tried to read the metadata but could not find any flag for this. Any help will be appreciated. Please find the metadata response below.

{
  "info": {
    "PDFFormatVersion": "1.7",
    "IsLinearized": false,
    "IsAcroFormPresent": true,
    "IsXFAPresent": false,
    "Title": "Resume",
    "Author": "LinkedIn",
    "Subject": "Resume generated from profile",
    "Creator": "Acrobat Sign",
    "Producer": "Acrobat Sign",
    "CreationDate": "D:20220323065214Z",
    "ModDate": "D:20220407204701-07'00'"
  },
  "metadata": {
    "_metadata": {
      "dc:description": "Resume generated from profile",
      "dc:creator": "LinkedIn",
      "dc:format": "application/pdf",
      "dc:title": "Resume",
      "dc:language": "en",
      "dc:date": "2022-03-23T06:52:14Z",
      "pdf:producer": "Acrobat Sign",
      "pdf:pdfversion": "1.4",
      "pdfuaid:part": "1",
      "xmp:metadatadate": "2022-04-07T20:47:01-07:00",
      "xmp:createdate": "2022-03-23T06:52:14Z",
      "xmp:creatortool": "Acrobat Sign",
      "xmp:modifydate": "2022-04-07T20:47:01-07:00",
      "xmpmm:documentid": "uuid:b6b37f58-7c64-2a45-5f0a-454c97be7809",
      "xmpmm:instanceid": "uuid:ccf84365-bc5a-2d90-5009-454c97be7809"
    }
  },
  "contentDispositionFilename": null
}