iStudiez Pro uses the system settings/preferences of your device.
If you want to see the time in iStudiez Pro in 24-Hour (Military) Time format, please enable this option in the System Settings/preferences app on your device.
For example, on iPhone : go to System Settings app > General > Date & Time > 24-Hour Time > enable the option.
Doing this you will get your time in iStudiez Pro shown in 24-Hour format.
And vice versa, disable the option if you want to switch to am/pm format.