Students at public universities in Germany are subject to a compulsory statutory health insurance until reaching the age of 30 – in certain cases also beyond. This also applies, if you do not reside in Germany (cf. SGB V, §5, Abs. 9; in Germany only). Therefore, you need to proof that you have sufficient health insurance for enrolment at the university as well as for the visa application and prolongation respectively.
In Germany there are two types of health insurances: the statutory and the private. New students may generally freely decide between the two, however this choice is binding for the complete studies. Usually, international students take out an insurance in Germany; the statutory health insurances decide on the possible recognition of a foreign health insurance.
Any person can be insured with a statutory health insurance and all insured person receive on the basis of the solidarity principle the same services. The student contribution rate (Website in German only) to the statutory health and nursing insurance is currently about 100 € per month (as of 2020) up to the age of 30; above that it is significantly more expensive. Students up to the age of 25 (possibly also older) with no or low income can be insured free of charge in the family insurance of their parents.
In contrast to the statutory health insurances private health insurances have the right to decide on whether they wish to insure a person and may determine individual insurance rates. They do this on the basis of criteria such as age, gender and state of health. Additionally, you need to pay attention that the agreed scope of services is sufficient for being released from the compulsory statutory health insurance. Privately insured persons mostly receive an appointment with a specialist quicker and higher-quality services when seeing a doctor or in a hospital than statutory insured persons.
Further information on the different health insurers is available here (German only).