Dear Aspirant,
You do not need some specific knowledge. However, if you are going to take admission in Computer science and engineering then you need to learn coding. This is the new thing which you did not have any idea of probably.
But no need to hurry, if you're going to take admission this year, then you have enough time to learn coding.
Just start with languages like C++, Java or Python.
These are easy as compared to C language which is primarily taught in first semester.

Watch YouTube video lectures. There are a lot of good lectures on YouTube.

Hope this helps.
Thank you.

Hi ! You just need a prior knowledge of c language if you did learn with computer. But if you studied with biology, then it will be a bit problem but never mind they always start freshly. So you just need basic knowledges of computer, chemistry, math and physics. So hope you understand and best of luck to you.