Sometimes when I'm using the Korean IME in Windows 10, I somehow accidentally trigger a menu to type hanja - but when I want to type hanja, I can't think how I did it! How do I trigger the hanja facility?
The '한자 키' on a Korean keyboard is usually the same key as the one that may be the right 'Ctrl' key on many countries' keyboards. This picture shows the key with both labellings :
If you type a hangul character that you want to 'convert' to hanja, and press the '한자 키' while it is highlighted, a menu will come up:
This shows the possible hanja for this hangul character on the left, with the 뜻 - 음 (meaning - sound) description on the right. Here, we have
'남녘 남' - 'south 남'
'사내 남' - 'boy/man 남'
'바구니 남' - 'basket 남'
And so on. These help you to choose which 한자 is the correct one.
Just to compliment the existing answer:
The 한자 key seems to work slightly differently based on the program it's being used on
The accepted answer shows how it is used in notepad in Windows, and it seems to work in 3 cases:
Type a Korean syllable block and press 한자 key: eg: type 한, then before pressing anything, while the computer is still accepting inputs for the same syllable block, press 한자 key to bring out the menu
Type a Korean syllable block completely, highlight the character with shift+arrow key and press 한자
Go to the beginning of a completed syllable block, press 한자
All the actions mentioned above have the same effect in Notepad
However, when typing something in a text box in Google chrome in Windows, only action 1. mentioned above works correctly. The 한자 keypress is ignored in other cases. I am supposing other programs might behave differently as well.