If you are not familiar with the game Ingress you have no use with this app. I recommend to check out the game ingress and choose the blue faction called Resistance.
Faction-only: Resistance. Passcoder is an app only for members of the Resistance. Make sure you know an approver before installing the app. without a secure code of an approver you will have no access to passcoder. If you have no approver near you as resistance, contact the developer.
Passcoder is an app to make to improve the distribution of passcodes. Distribution is done trough a collaboration system and redeeming a passcode is very easy. Don't miss any passcodes with passcoder.
Access for the app will only be granted trough a verification system.
Passcoder is not made by Niantic, creator of Ingress. Passcoder is a standalone application and is not against the ToS of Ingress. As distribution platform nothing is automated and everything is manually controlled by the users itself.