Run following commands to enable your Raspberry Pi.

sudo apt-get install ibus
sudo apt-get install ibus-hangul
sudo apt-get install fonts-unfonts-core

Now you will be able to  navigate Korean website like NAVER, DAUM, and etc.

In addition, you will need to run below command for using your Hangul key.

sudo apt-get install fcitx-hangul

And please follow following procedure to activate all the necessary things:

Raspberry Pi → Preference → Input Method → Click Okay → Click Yes → Select "fcitx" and click OK → OK

Now what you have to do is just rebooting on command line