A little more information is required. Your question is like “What can you do with an MBA?”
And since you are currently an undergraduate or high school student it is completely premature.
@TomSrOfBoston … I do mean careers. For example, a J.D. allow one to practice law to become a lawyer or a politician. I am asking what careers you can do with the LL.M. degree. What does it allow one to become?
Some law professors have an LL.M., though most law professors only have a J.D.
An LL.M. might be obtained in specialized areas of law, such as Legal History, Intellectual Property, International Law, or Environmental Law. As I understand it, it is generally considered more useful for a legal scholar, rather than for practitioners.
To get an LLM you must first have a JD.
As a tax guy (CPA) we often see tax attorneys with an LL.M. in taxation.
I know of one university that offers their graduate program in taxation as an LL.M. for attorneys or Masters in Taxation for accountants.