Hello Krishnamohan!
If you want to become a teacher, you need to proceed in the way (whichever applicable to you) mentioned below :-

1. For Primary School Teaching :-
If you are willing to become a PRT (i.e. teaching children generally belonging to the age group of 6-12 years), you can pursue any one of the following courses after qualifying Class 12th Board exams :-
*ETE : Elementary Teacher Education
- Duration : 2 years
-Institutes which you can join for ETE are : District Institution of Education and Training (DIET) in Bhopal, Ramakrishna Teacher Training Institute in New Delhi etc.

*B. El. Ed. : Bachelor's in Elementary Education
- Duration : 4 years
- Institutes offering this course : University of Delhi (DU) , Bansidhar Mahavidyalaya in Uttar Pradesh etc.

*D. El. Ed. : Diploma in Elementary Education
- Duration : 2 years
- Institutes offering D. El. Ed. : District Institute of Education and Training in Tura, Primary Teacher's Education College in Bhojpur etc.

2. For Secondary School Teaching :-
If you want to serve as a TGT (Trained Graduate Teacher) and teach the students of Class 6th to 10th, then you can pursue a Bachelor's degree in any teaching subject, preferably - B.Com. (Honours) or any subject from humanities stream of your choice.
After completing your graduation, you will have to pursue Bachelor's in Education (B. Ed.) course from any recognized institute. This course is of 2 years duration.
- Institutes that offer B. Ed. course are :- University of Delhi, Guru Govind Singh Indraprastha University, Banaras Hindu University and many others.

3. For Senior Secondary School Teaching :-
If you want to work as a PGT (Post Graduate Teacher) and teach students of Class 11th and 12th, then after completing your graduation in any teaching subject, you will have to pursue a post-graduate degree or Master's degree in any relevant discipline (for eg. M.Com. if you are interested).
-You also need to have completed your B. Ed. from a recognized college or university in addition to this.
Also, for teaching in Central and State govt. schools and colleges, you will have to qualify CTET (Central Teacher Eligibility Test - for schools under central govt. like Kendriya Vidyalayas) or STET (State Teacher Eligibility Test - for institutes under a particular State govt.).

4. For Teaching in Higher Educational Institutes :-
If you want to teach the students of colleges and universities and become a Lecturer or Professor, then after getting your Masters' degree, you will have to qualify UGC-NET (acceptable in institutes all over India) or SLET examination (acceptable only in the institutes of a particular state which is conducting the exam).
Remember that a degree in B.Ed. is not required to become a Lecturer/Professor.

Feel free to ask if you have any further queries in this regard.

I hope this answer will help you.

Hello Aspirant,

There are many ways you can join as a teacher.

After passing your class 12th, you have to pursue your graduation in your interested field. Having passed the Graduation with at least 45% marks and passed or appearing in 1st year  Bachelor in Education (B.Ed)/ B.Ed. (Special Education)/Senior Secondary (or its equivalent) with at least 50% marks and passed or appearing in final year of 4- year Bachelor in Elementary Education (B.El.Ed)/ B.A/B.Sc.Ed or B.A.Ed/B.Sc.Ed.

There are many ways you can join as a teacher.

After passing your class 12th, you have to pursue your graduation in your interested field. Having passed the Graduation with at least 45% marks and passed or appearing in 1st year  Bachelor in Education (B.Ed)/ B.Ed. (Special Education)/Senior Secondary (or its equivalent) with at least 50% marks and passed or appearing in final year of 4- year Bachelor in Elementary Education (B.El.Ed)/ B.A/B.Sc.Ed or B.A.Ed/B.Sc.Ed.