It is regulated by law who can/must participate in an integration course. However, you are free to choose the provider with whom you complete this course. The integration course consists of a language course (600 lessons) to acquire sufficient language skills (language level B1 of the Common European Framework of Reference for Languages) and an orientation course (60 lessons) to impart knowledge of the legal system, culture and history of Germany.
The integration course is completed after successfully passing the exams "German Test for Immigrants (DTZ)" and "Living in Germany". If you pass the DTZ with an overall score of B1 and have also successfully completed the "Living in Germany" test, you will receive the Integration Certificate from the Federal Office for Migration and Refugees (BAMF). The cost of the integration course for the participant is 1.95 EUR per lesson. There is the possibility of a cost exemption.
You can also find information from the BAMF here.