mkdir() help

[DeaD_EyE]

Put a print statement around os.getcwd()

def make_file():
   print('Current working directory', os.getcwd())
   os.chdir('export')
   os.mkdir(str(name.get())) 

Execute the program and look in which current working directory your program is running.
Look if you can reach from this path 'export'. I think your cwd is at a different path
as the directory 'export'.

By the way, os.mkdir makes a directory, not a file.
If you want to read/write file, use open(filepath).

After you've understood the old school os.path and the difference between relative and absolute paths, you should take a look into the pathlib module.