You can change PDF properties by using Syncfusion’s Essential PDF (.NET PDF library).
The whole suite of controls is available for free (commercial applications also) through the community license program if you qualify. The community license is the full product with ...
This is a simple job and theoretically any PDF library should be able to do it.
With PDF4NET you can do it like this:
PDFFixedDocument document = new PDFFixedDocument(pdfFileName);
if (document.DocumentInformation != null)
document.DocumentInformation.Author = "";
document.DocumentInformation.Producer = "";
// Save it only ...