Hi @NishithVPoojary-0251 ,
UART is byte stream interface.
If you want to split it into specific lengths, you have to implement the code.
Sample code is here.
The received data is stored in the ReceiveBuffer, and meaningful chunks of data are passed to the MessageReceivedHandler.
https://github.com/matsujirushi/uart-to-azureiot/blob/master/app/uart-to-azureiot-hlapp/main.c#L254