Company secretary itself is a course. You need to give your 10+2 from commerce stream and then you can choose company secretary as your graduation field. It has great scope. You need to give the ICSI examination. It can be choosen for postgraduation as well. You will need to go through these 3 parts -

1.Foundation Programme

2.Executive Programme

3.Professional Programme

After all exams you will have to work under practicing CS for 9 months.

Their earning is quite high. You can have a salary package ranging from 10-20 lakhs per annum.

refer to the the site below for more detailed information..

https://university.careers360.com/articles/company-secretary-cs

Best wishes. Thank you.