I like to test Python in different situations, it just makes my life easier in many situations. Python allows me to automate things that are normally repeated and boring, so I can focus on important aspects of my job. Today I will show you how can you edit PDF files with python.

In this example I will be using ReportLab.
The ReportLab Toolkit. An Open Source Python library for generating PDFs and graphics.

This is our original pdf:

Let's jump to the code!

First we need to import dependencies

from PyPDF2 import PdfFileWriter, PdfFileReader
import io
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter

First we will create a new PDF with Reportlab, in this part we will also define our font color and the font size:

packet = io.BytesIO()
can = canvas.Canvas(packet, pagesize=letter)
can.setFillColorRGB(1, 0, 0)
can.setFont("Times-Roman", 14)
can.drawString(72, 655, "Hello from Python")
can.save()

Then we move to the beginning of the StringIO buffer:

packet.seek(0)
new_pdf = PdfFileReader(packet)

read your existing PDF

existing_pdf = PdfFileReader(open("original.pdf", "rb"))
output = PdfFileWriter()

The we add the "watermark" (which is the new pdf) on the existing page;

page = existing_pdf.getPage(0)
page.mergePage(new_pdf.getPage(0))
output.addPage(page)

And finally, write "output" to a real file:

outputStream = open("destination.pdf", "wb")
output.write(outputStream)
outputStream.close()

This is our result:

Thank you all.