As you have completed B.Tech in Electronics and Communication Engineering, there is a vast field of job opportunities available for you.
To get government jobs you have to qualify in written test of various state level or national level exams.
There are also numerous prospects in the Central government departments like Defence, Railways, Airport Authority, Post and Telegraph, IES, and others You can get a job in these departments by qualifying in the tests conducted by Union of Public Service Commission (UPSC) and Staff Selection Commission (SSC) and others.

You can also make a career in PSU. Some of the PSU’s recruit aspirants who have completed B.Tech in ECE are given below.

Bharat Sanchar Nigam Limited (BSNL)
Bharat Electronics Limited (BEL)
Bharat Electricals Limited
Oil and Natural Gas Corporation Ltd (ONGC)
Steel Authority of India Limited (SAIL)
Mahanagar Telephone Nigam Limited (MTNL)
Indian Space Research Organisation (ISRO)
Indian Oil Corporation Ltd. (IOCL)

These companies take written tests and interviews or select according to the GATE score.

You can also join private companies like Reliance, Nokia, Tata, LG, Wipro, Infosys, TCS, and others.