You do not need a visa to come to Prague for the TEFL course if you are from Europe, Australia, Canada, the US, and some South American countries. If you are not from one of the listed countries, contact the Czech embassy in your country and if needed we are willing to provide you the Accommodation and Invitation letter for the getting the tourist visa. The allowed length of stay in the Schengen zone (most of Europe including the Czech Republic) is 90 days.
If you want to live and work in the Czech Republic, we will provide you with information and give you a visa agency contact. The visa agency will help you to go through the visa process. You have to apply for a long-term visa.
For more information, you can reference this website.