Selecting a course

Masters 
IELTS is mandatory if you are not from an english speaking country. GRE is not mandatory for all the universities but it will give you a better chance of getting an admission

www.mastersportal.eu
www.daad.de/en/

Bachelors 

Compared to masters very limited courses are offered in english. You could do bachelors if you study german (B1 or B2: depends on the university) from your home country or from Deutschland.After succesfully completing the language course , you will be asked to take an entrance exam ,based on your results you can apply for bachelors at the university

Types of Universities

TU - Technical Universities
if you are planning for a career in research this will be your best option . More of theoritical approach

Universität - Eg: Karlsruhe institute of technology
Theory + Practical oriented

FH or HS -Fachhochschule or Hochschule

Generally known as university of applied sciences .

More of practical oriented studies with limited number of departments. Mostly specialize in a certain technology

Fees
Fees structure depends on the state or the region your university is located. All government universities offer free education but you will be required to pay enrollment/donation/service to the government via university or through city office