PDFont font = PDType1Font.HELVETICA_BOLD;
PDPageContentStream contentStream = new PDPageContentStream(doc, page);
contentStream.beginText();
contentStream.setFont( font, 12 );
contentStream.moveTextPositionByAmount( 100, 700 );
contentStream.drawString( message );
contentStream.endText();
contentStream.close();
doc.save( file );
}