No, Users Flow is a plugin that is built on top of Matomo (Piwik). To use it, you first need to install Matomo.
Matomo requires PHP, a MySQL database and a webserver like Apache or Nginx. Learn more about Matomo.
Alternatively, to take away the hassle of installing and maintaining your own Matomo, signup to our Matomo Cloud service.

Previous FAQ: Does the plugin slow down tracking or require any additional storage in the log database tables?