How do I organize my simple ftp modules?

[Gribouillis]

But, anyway, is this a correct usage of the keyword global?

Normally people try to avoid the global keyword by not assigning to global variables, and when they use it they tend to minimize the number of variables using global. This is normally achieved by encapsulating variables in classes. Here is how you could write the same code without this keyword by introducing a FtpUser class for example

from ftplib import FTP
import os
import configparser


class FtpUser:
    def __init__(self, address, name, password):
        self.address = address
        self.name = name
        self.password = password

    def download_all(self, localPath):
        ftp = FTP(self.address)
        ftp.login(user=self.name, passwd=self.password)

        ftpFileNames = ftp.nlst()

        for ftpfileName in ftpFileNames:
            if not isDir(ftp, ftpfileName):
                localFileName = os.path.join(localPath, ftpfileName)
                localFile = open(localFileName, "wb")
                ftp.retrbinary("RETR " + ftpfileName, localFile.write, 1024)
                localFile.close()

        ftp.quit()

    def __repr__(self):
        return f"{type(self).__name__}({self.address!r}, {self.name!r}, {self.password!r})"

    @classmethod
    def from_init_file(cls, parametersFileName, section="myvars"):
        config = configparser.ConfigParser()
        config.read(parametersFileName)

        return cls(
            config.get(section, "ftpAddress"),
            config.get(section, "ftpUserName"),
            config.get(section, "ftpPassword"),
        )

import my_ftp

ftp_user = my_ftp.FtpUser.from_init_file("C:\\Users\\Python\\config.ini")
print(ftp_user)  # here i'm checking if the variable's value are ok
ftp_user.download_all("C:\\Users\\Python\\")

As a bonus, this code allows you to enter several ftp addresses and users in the config file under different section names.

Read PEP 8 to learn about variables and functions naming conventions usually chosen in Python code.