from where I can prepare for bca entrance exam
Hello,
You haven't specified the name of BCA entrance exam, but in general there can be questions from general awareness for which you can go through GKToday to cover static portion, for dynamic portion read newspaper on a daily basis, for numerical ability you can go through NCERT book or refer any other standard book such as Arihant Publication's Objective Mathematics, for English refer Wren and Martin Grammar book, for reasoning you may refer RK Agarwal's Modern Approach to Verbal and Non-Verbal Reasoning. computer awareness too is part of syllabus so you need to be well acquainted with this portion, you can refer to YouTube channels for competitive exams which has this portion, or search the Internet extensively regarding this, this is just a general viewpoint I have given, to provide you specific details you should mention the name of the exam as it's not the same exam pattern for all colleges, you can search out site regarding the details though.