Small update recommendations
The image order for the before and after of the pdf document makes it appear as though the file is receiving a watermark. I believe you should change the order of the images in the readme layout.
Also, you could make the application more straightforward by using tkinter's filedialog function to get the file path.
The program should also have comments and the erroneous code segments should be removed as well. Github will keep track of those changes for you in the event that something does break in the process.
Would also like to request that the python version used to create the program be included so that changes can be easily researched
I looked at your suggestion, submitted to my own repository, and then submitted a PR, I didn't use tkinter because the CLI approach is more service-friendly. Also, I didn't find a preference for the python version of this program (currently I'm using Python 3.11)