Hello, You can check your registered Mail ID for application no. If you cannot find then You can find your application number in challan if you have paid the cet fee, you will be having that candidate copy with you . for example- KEA Ref Number 1144552001 it will be given. In that neglect the first number , & from second number it should be 6 digit number for your application number i.e for the given number it should be 144552 .
If you cannot, you need to contact its official-
Phone : 080 - 23460460
E-mail:keauthority-ka@nic.in

Hope it will helpful for you :)