Hi Bhargav, I hope you're doing well!
The connectivity stacks developed for the KW41Z family of MCUs was developed alongside a Connectivity framework. This framework has some critical components designed with connectivity applications in mind, among these is the Serial Manager, which can help with setting up and transmitting data by using different types of Serial Interfaces.
For a guide on how to set-up and use a Serial Manager instance, could you please take a look at this document?
The Connectivity Framework Reference Manual is also a good source of information about the Serial Manager API, it can be found in the following path in the SDK:
<…\SDK_SDK_2.2.1_FRDM-KW41Z\docs\wireless\Common\Connectivity Framework Reference Manual.pdf>
Please let me know if you need any more information.
Best regards,
Sebastian