How do I write from the back of the file?

Write open(fildname, "a") The second factor in open is related to the mode of reading and writing files.

The difference between r+ and a+ is in current look position. If you open it with r+ and write it right away, write it from the front of the file If you open it with a+ and write it right away, write it from the back of the file.

with open("test.txt", "a") as myfile:
    myfile.write("appended text")