@VamsiChukkapalli I don't know exaclty how is the PDF in your section.

Anyway, maybe this can help you. Use the following java function to merge 2 PDF encoded in base64. It will return a string which is the merged PDF encoded in base64

/*
INPUT PARAMS
------------
b64pdf1 : String
b64pdf2 : String

IMPORTS
-------
java.io.ByteArrayInputStream
java.io.ByteArrayOutputStream
org.apache.pdfbox.pdmodel.PDDocument
org.apache.pdfbox.multipdf.PDFMergerUtility
*/

String result = "";

try {
  PDFMergerUtility PDFmerger = new PDFMergerUtility();

  PDDocument destination = PDDocument.load( new ByteArrayInputStream(Base64Util.decodeToByteArray(b64pdf1)) );
  PDDocument source      = PDDocument.load( new ByteArrayInputStream(Base64Util.decodeToByteArray(b64pdf2)) );

  PDFmerger.appendDocument(destination, source);
  
  // APPEND SOURCE TO DESTINATION
  PDFmerger.mergeDocuments(null);

  // SAVE TO OUTPUT STREAM
  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  destination.save(baos);

  // GET THE BASE64-ENCODED PDF
  result = Base64Util.encodeToString(baos.toByteArray());
  
  destination.close();
  source.close();
}
catch(Exception e) {
  //
}

return result;