Method 1: QRCode scanner, each registered user has a unique QRCode ID and the code is used to clock-in through the scanner for attendance tracking.
Method 2: GPS, each registered user can provide his/her geolocation for clocking-in.
The app also support cross-plaform access,
for PC please visit http://www.liensquare.com/ezclocking/
for iOS please download the app at https://itunes.apple.com/lu/app/ezclocking-client/id929191995?mt=8
for user manual visit http://www.liensquare.com/ezclocking/v2/help.html