To become an engineer, you should first enroll yourself in the engineering colleges and then you can study hard and become engineer. Some of the important entrance exams of all the top colleges are enlisted below:

JEE Mains examination - it will help you to get admission in IITs and NITs. After qualifying this examination, you can appear for jee advanced.

Srmjeee - to get admission in SRM, Chennai 

Viteee- to get admission in VIT, Vellore 

Kiit- to get admission in Kalinga institute, Bhubaneswar

Comedk- to get admission in various colleges of Bangalore. 

Apart from these, you can also give many more entrance exams and enroll yourself in good colleges accordingly. 

Good luck!! 

Hello Inayat
To become an engineer you have to give some competitive examinations for government and private institutions too
Some are as follows-
JEE Examination
AKTU
VIT Entrance Examination
UPESEAT
COMEDK UGET
SRMJEEE
SMIT
KIIT
GEEE
Amity JEE
But inayat u are a bit late coz initial step of JEE Examination that is JEE mains application last form filling date is also gone
So you cannot sit in that examination process
Moreover you have chances for other Examination but do fast because there is a time limit for every forms . So make sure you are filling forms as per your criteria of choosing colleges .
And for clearing these examinations you have to study hard start practicing mathematics physics and chemistry firstly from NCERT then from optional books