Hello Ganavi,

It is very important to have the challan.But if you have written the exam, and the results are out then it is really not complusory to carry the challan. Your other documents like rank card,caste certificate(if present), marks card of 10th and 12th will do.The challan is not complusory. 

Hello!!!

If you have paid online through net banking or debit card then you must provide a proof of your transaction history. But if you pay through challan then you will have to download the form  which kcet has provided in its official Website. Then in the bank you need to pay the fees and you will get the challan receipt which will have the challan no.