Actually it depends on context.
There are lots of meaning in it.
Here are some examples of it's usage.
Take care! (at the end of a letter)
잘 지내. (as Jung mentioned)
Take care of yourself.
몸 조심 하세요.
I will take care of it.
내가 알아서 할께(I will deal with it, I will cope with it, I will manage it)
Please take care of my sister.
내 여동생 잘 보살펴줘(look after my sister)
Take care on the way home.
집에 조심해서 잘들어 가세요.
Take care! (see you later, see you soon)
잘가