The most common work visa in the U.S. is the H1B. Your employer will sponsor your visa, which will enable you to work in the U.S. for 3 years. They can also help you extend your H1B visa by 3 more years. Once you finish your 6 years, your employer can choose to file an I-140 petition, which enables you to stay in the U.S. as long as your green card application is in progress.