Hi basilmathew@alemadi.com.qa,
To have the capability to download the code automatically from Simulink to the NXP target you need to flash a bootloader on the actual microcontroller. This bootloader can be flashed with the CW for MCU using a JTAG probe. You need to do this only once since the bootloader is resident in the flash. Later on – this bootloader will allow you to load code directly from USB or CAN interfaces into the microcontroller memory.
Below is the overview of the process:

#1: Install NXP CodeWarrior 10.7 or newer from the official page here
#2: Create a bareboard stationary project for the MCU you are using:

#3: Open the Flash File menu and select the RBF file associated for that MCU

#4: Make sure the JTAG connection is configured correctly and click on ERASE and Program button
Once the RBF is flashed into the MCU memory then you can download the code automatically from Simulink or from RappID bootloader UI.
Hope this helps!
Daniel