TEFL (Teaching English as a Foreign Language) is a standard certification for English teachers. As you may not have this certification right now, you will have to take a TEFL course to obtain one. There are many certifications available starting from an intensive weekend online course to face-to-face 30-day certifications.
The course will teach you all the basic things an English teacher should know. You will get the foundation needed to become a successful teacher – starting from how to engage learners and how to help them gain knowledge all the way to special techniques of teaching in online settings.