Galaxy S4 option to move to SD card is grayed out?

[Peele]

Facebook is 256MB and resides on my S4 device and I need the memory. Why are certain apps grayed out? How can I free up memory?
Thanks,
Peele

 

[hang-the-9]

Many apps you can't move to the SD card without a bunch of tricks, including rooting the device. If you are interested with messing around more with that you can find plenty of tutorials with a web search on how to move apps to sd card.