converting int or float into bytes array in arduino

I am trying to send data from one arduino to another over ethernet using udp protocol. In arduino writing data over udp is like this

UDP.write(buffer, size);

where buffer is an array to send as a series of bytes and size is the size of the array.

Now, i am reading a sensor value from a0 pin of the arduino it will be stored either in int or float type variable. As mentioned earlier udp only sends byte type array. so all i want to do is convert the value stored in the variable to the byte type array. my variable will be.

pinMode(A0,INPUT);
int data;
byte data_array[Size];

and in loop

data=analogRead(A0);

now i have convert this value in data_array;

Please provide the suggestion with proper explanation. Thank you