The qualifications needed to become a TEFL teacher vary between different countries. In some countries you don’t need any qualifications at all and in others you do.
In many countries though, you will need a degree and a TEFL certificate. Additionally in some countries there is no official requirement for a specific qualification but in practice a TEFL certificate is almost always required to get a job.
We suggest that you check the requirements for the specific country that you plan to work in.