From the home screen, swipe down from the Notification bar. Note: The Samsung Galaxy S4 is available with 16/32/64GB of internal, usable memory and the option to add a MicroSD card (sold separately) up to 64GB.
Tap the Settings icon.
Swipe to the MORE tab, then tap Storage.
The device storage summary will be displayed beneath Device memory.
Scroll down to view the available memory card space.
To free up memory on your device, delete unwanted pictures, music, and videos by tapping Apps > navigate to the desired app > tap the desired media > tap the Delete icon.
Remove unused apps by tapping Apps > touch and hold the desired app > drag it to Uninstall > tap UNINSTALL.
Clear app data by swipe down the Notification bar > tap the Settings icon > Under the MORE tab, tap Application manager > tap the desired app > tap CLEAR DATA.
Download a cloud storage app by tapping tap Play Store > Navigate to the desired app > tap INSTALL and follow the prompts to download.
Purchase an SD memory card to expand your device memory.