@vaibhavi_padwal
Can I suggest that you follow @ErichStyger suggestion for FreeRTOS?
It's supported natively by MCUXpresso and @ErichStyger has a number of excellent articles explaining how to enhance the experience.
I've worked with MQX on the MK20 and, over the years, I've worked with quite a few different RTOS's and there aren't a lot of basic operating features that really make one RTOS better than the others but if you have one that is integrated into the IDE, like FreeRTOS is, it makes all the difference.
Good luck!