PDPageContentStream contentStream = new PDPageContentStream(document, page);
contentStream.beginText();
contentStream.setFont( font, 18 );
contentStream.moveTextPositionByAmount( inch, ph-inch-18);
contentStream.drawString( "PDFBox" );
contentStream.moveTextPositionByAmount( 0,-(inch/2));
contentStream.drawString( "Click Here" );
contentStream.endText();
contentStream.close();