Additionally, Apple sometimes releases software updates designed to resolve freezing problems.
You can update your device by plugging it into your computer, opening i Tunes and clicking “Update” in the device summary menu.
If this doesn’t resolve the issue, or you cannot power on your fully charged i Phone, try resetting the device.
Restoring your i Phone is a time consuming process that you should only undertake if your i Phone is still freezing after you’ve tried the previous steps.
To restore your i Phone, connect it to your computer with the USB-i Phone connector, select your i Phone in the “Devices” menu and navigate to the “Summary” tab.
If there isn't enough space to download and install an update, i OS will try to make space.
It will remove only app data that it can download again and doesn't remove or relocate any of your data.