You can do below things after your graduation in engineering-

1- Plan Out Your Further Studies by Specializing ie. M.Tech: Pursuing your further studies is another option to choose after completing your B.Tech studies. M.Tech is the next step that allows you to select your field of expertise and excel in it.

2- Shift over to the Business Side i.e., MBA: If management and business has ever been interesting then you should consider pursuing MBA. Master’s in Business Administration (MBA) is also a largely pursued course in India and has a lot of scope. Fields such as HR, Marketing, Digital Marketing, International Relations, Sales and more are some of the well-known and preferred specializations.

3- Diploma Courses: Pursuing diploma courses is another alternative which will be available for B.Tech graduates. Courses such as embedded technology, VLSI, robotics, ethical hacking, protocol testing, machine designing and more are some specialized courses to name a few. These short term courses and diplomas are usually job oriented and will be helpful while applying for jobs in different industries.

4- Crack the Civil Service Examination: One of the toughest examination of our country, the Civil Service Exam falls under the category of the most attempted examinations. For engineering graduates, there is the IES in addition to the civil services one. If you feel that a government job will provide you with much better facilities and a safeguarded future, then start preparing for the civil service examinations. You will face a tough competition ahead but with a hardworking mindset, the job can be done. After the examination, an interview will be conducted which you will have to qualify before proceeding for training.

5- Serve your country: Apply for AFCAT (Air Force Common Admission Test) which can land you up as a technical staff in the defense wing. The facilities provided for defense staff are good and the pay scale too while fulfilling your passion to serve the country.  

Good Luck!!