Create a normal FTP account from CPanel / from a domain.
After that, pull up My Computer or Windows Explorer and enter the ftp address in the address bar, something like this:
ftp:username@yourdomain.com
username: username@yourdomain.com
password: the password you set before.
That’s it, you should see the public folder from where you can copy/paste files.
You can share the login details with anyone you want to share files.