Computer Science

The application form is available at it's central office you can get it from there the charge is about Rs 25 or by sending bank draft of Rs 50 in favor of it, shortlisting is done on the basis of merit.

I hope this link will do it:
http://www.psgtech.edu/hme.php?var=CSE.

For pursuing B.Sc in CS/IT you need science stream in your 12th without it you are not eligible for B.Sc because B.Sc CS includes maths, computer and physics as main subjects.

You can do even this by searching the institution on the google maps and later on for choosing the best one, you should take feedback from their past students and you can find out your needs by doing this. Thanks, don't forget to upvote. EDIT: Also, as Kanishk said you can visit such recommended institution and then take feedback.

Go for IITs as it's good for placement. Attempt for JEE.

No, you will not eligible for GATE exam. But, you can do higher studies like PHD and other courses.

Yes, but the quality of college you get may not be of high standard.

You can try to specialise in bioinformatics, connectivity, gaming tech, cyber security, data analytics.

No need to have good marks. Placements only depend on your skills and knowledge like you are a good programmer then only you will get hired. Suppose, you don't like programming, but you are perfect in networking or designing field, you will get a job easily. In earlier days, the network engineering had a good demand in the market so take your choice and go ahead.

Firstly, you need to decide where you wish to apply. Thereafter, see if you meet their criteria for pursuing Ph.D. The minimum qualification required is PG or some national level exam such as GATE JRF etc. You must have obtained either a minimum of 50% marks or equivalent grading in the M.Phil. Degree or a minimum of 55% marks or equivalent grading in the Master's degree.