If you already have your bachelor's degree in history, but do not have a teaching certification, you can enroll in a master's degree program in education online to gain certification. An M.Ed. will prepare you for teacher certification and allow you to take advanced history courses. These master's programs do not require you to have a background in education or education courses.
Teacher certification courses give you the ability to take only the necessary courses in teaching and history online without having to pursue a master's degree. There are several different types of teaching licenses: early-childhood programs, elementary grade certification, specialty certifications such as music that allow you to teach grades one through 12 in your specialty, and subject-specific licenses. To teach history, you will need a subject-specific license that will allow you to teach history in grades seven through 12. There are many certification courses online for those who already have a degree in education, and there are full degree programs for those without a bachelor's degree.
Most states require you to pass a state licensing exam in addition to finishing your bachelor's degree and teacher certification to teach history. By far the most common test is the Praxis test, administered by the Educational Testing Service at locations throughout the United States. There are two parts to the Praxis test: the first part is about general educational knowledge and the second part is about the specific subject for which you are seeking a teaching license, in this case the subject is history. The Praxis test can not be taken online, but there are test locations in every state.
While you can take all of your education courses online, you can only fulfill your student teaching requirement in person at a traditional institution. Student teaching can take from a few weeks to a full semester. Some states require student teaching and others do not; it is possible to get your certification completely online in the states that do not require student teaching.