This technical tip shows how developers can add text in header or footer of a PDF file  inside their Android applications. The TextStamp class is used to add text in PDF document. We can also use the same class to add text in Header/Footer area of PDF file. The TextStamp class provides necessary methods to specify font size, font style, and font color etc for stamp object. In order to add text in the Header area, first you need to create a Document object and a TextStamp object using required methods. After that, you can call addStamp(..) method of Page class to add text in the PDF file.   Please note that when placing text in Header section, you need to call setTopMargin(..) in such a way that it adjusts the text in the header area of your PDF. Similarly when placing text in Footer section, you need to call setBottomMargin(..) in such a way that it adjusts to the text in Footer area.

• When adding stamp object in Header section, you also need to set VerticalAlignment to Top.
• When adding stamp object in Footer section, you also need to set VerticalAlignment to Bottom.

//open document
com.aspose.pdf.Document pdfDocument = new com.aspose.pdf.Document("/mnt/sdcard/input.pdf");
//create text stamp
com.aspose.pdf.TextStamp textStamp = new com.aspose.pdf.TextStamp("Sample Stamp");
//set properties of the stamp
textStamp.setTopMargin(10);
textStamp.setHorizontalAlignment(com.aspose.pdf.HorizontalAlignment.Center);
textStamp.setVerticalAlignment(com.aspose.pdf.VerticalAlignment.Top);

//set text properties
textStamp.getTextState().setFont(new com.aspose.pdf.FontRepository().findFont("Arial"));
textStamp.getTextState().setFontSize(14.0F);
textStamp.getTextState().setFontStyle(com.aspose.pdf.FontStyles.Bold);
textStamp.getTextState().setFontStyle(com.aspose.pdf.FontStyles.Italic);
textStamp.getTextState().setForegroundColor(java.awt.Color.GREEN);

// iterate through all pages of PDF file
for (int Page_counter =1; Page_counter<=pdfDocument.getPages().size();Page_counter++)
{
    //add stamp to all pages of PDF file
    pdfDocument.getPages().get_Item(Page_counter).addStamp(textStamp);
}
//save output document
pdfDocument.save("/mnt/sdcard/TextStamp_output.pdf");