how to convert an integer to binary in Arduino?

I have been trying with different data types and nothing is working.

How about posting what you have tried and describing what does not work as you want ?

I want to send in HEX and receive in HEX and i want to process as BINARY

HEX representation of numbers is only a way of making the value easier to read for humans. All values in the program are inherently binary behind the scenes. Unless, of course, you want to send and receive a series of characters representing the HEX value