The way you worded that question makes me think you're not from the US, but here are the requirements for American educators:

- 4 years of college
- Bachelors Degree in Education (preferred)
- Internship (preferred)
- Certification by the state that you live in

((Teachers roughly start out making between $30,000 and $50,000 depending on what state you live in))

For promotion:
- Normally 5 years of experience
- Masters Degree or higher in specified field

((Principals usually make over $100,000 but I think that reflects on the city, county, or state you work for))