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 (formerly Piwik Cloud) service.

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