hello aspirant,
after completion of your engineering, you can go with below of any of the exam to pursue higher studies in germany
they are:

• GRE (Graduate Record Examination) which is widely accepted in German universites for admission of students in postgraduate courses
• GMAT (Graduate Management Aptitude Test) ,the exam which we can pursue higher studies regarding postgraduate courses like management, business and finance

also, regarding language proficiency, you can go for IELTS, and TOFEL which are the two main prestigious exams that so many students take up to do their higher studies in germany.
thank you