Anything exists really. A boat exists, a planet exists Something that lives is an animate object; it has life which is DNA. DNA , deoxyribonucleic acid forms the building blocks to any sort of life-form.

Is this a philosophical question? If not, I'm going to say that "living" involves humans, plants or animals that are alive; whereas "existing" refers to inanimate objects.

I think they are similar. However, there is a difference. Let me use an expression as an example. I might say something like this: "I want to live. I don't want to merely exist." By 'I want to live', I mean that I want my life to have meaning. I want to do something with my life. By 'I don't want to merely exist', I mean that I don't want to just sit and do nothing. I don't want to just breathe and have a beating heart. I want to do more actions to make my life have meaning. Ok. I hope that example was helpful