In the United States, a Juris Doctor (JD) degree is required before sitting for a state bar exam, which after achieving a passing grade on that exam will earn you a license to practice law in that state only. The JD is pursued after 3 years of study and after having earned a 4-year bachelor's degree at the undergraduate level.
Individuals who are educated in countries outside the USA oftentimes earn undergraduate degrees that are the equivalent of a JD. However, if that individual wishes to take a bar exam in the USA, they must earn a Masters in Law (LLM) degree in the US before they are eligible to sit for the state bar exam. An LLM is one year of study. Individuals who earn JDs in the USA may also earn an LLM but usually do so in order to specialize in specific fields such as taxation or international law.