Uploading the WordPress files via FTP

If you don’t know what your root directory is, contact your hosting provider

and ask, “What is my root directory for my account?” Every hosting provider’s
setup is different. On Lisa’s Web server, her root directory is the public_
html folder; some of her clients have a root directory in an httpdocs folder.
The answer really depends on what type of setup your hosting provider has.
When in doubt, ask!