WPS Connect is an Android application that allows you to connect to WiFi networks without using a password.
What the app does is exploit the vulnerability in the router's WPS (WiFi Protect Setup), which is a means that was created to facilitate quick access of devices without the use of a password.
However, some devices, usually that do not have their firmware up to date, have a vulnerability that, if exploited, it is possible to access WiFi without needing the password.
It is a tool that can be used to check whether your device is vulnerable or not.