I used the Cell property which did not have editable selected to edit to edit the cell. Thank you the cell method worked.

Unfortunately I tried it myself, it seems it can't be done((( For this I usually use this source https://edusson.com/research-paper-writing-service which deals with research paper writing services; it actually means that they do absolutely any type of writing, including could do what you need. Another way I don't see, especially since it will be done in a very short time and with maximum quality, of the minuses is that you will have to pay, but in return you won't have any problems with it.

Change the path to the input file for Windows

CopyFile["/Library/Wolfram/Documentation/13.0/en-us/Documentation/\
English/System/Guides/GraphModifications.nb", 
 FileNameJoin@{NotebookDirectory[], "MyGraphModifications.nb"}]

NotebookOpen[FileNameJoin@{NotebookDirectory[], "MyGraphModifications.nb"}]

Select all cells Command-a on a Mac. From the menubar Cell / Cell Properties select Editable. You can now make changes to the notebook. However, File / Save is disabled, not sure how to enable it. Have to use Save As and overwrite the file.

I think I might need to enlarge the search of FindFile I have used a tool that searches my entire drive named VoidTools everything to search for GraphModifications and I found it.

See this answer on MSE. It does not work on v13+ since the documentation is installed separately. On MacOS change the first expression to

guideNotebooks = {"/Library/Wolfram/Documentation/13.0/en-us", 
     "Documentation", "English", "System", "Guides"} // FileNameJoin //
    FileNames["*.nb", #] &;

Unfortunately, there seems to be no cross-platform global symbol that points to the install location for documentation in 13+. The locations are documented here.

Windows: C:\Users\username\AppData\Local\Programs\Common\Wolfram Research\Documentation.en-us\13.0\Documentation

Macintosh: /Library/Wolfram/Documentation/13.0/en-us

Linux: /usr/local/Wolfram/Mathematica/13.0/Documentation