Hello @Ajay1202,
You can use the ble_fsci_black_box (inside wireless_examples > bluetooth > ble_fscibb) application from the KW38 SDK as base. FSCI should support UART, SPI and I2C.
Although I2C should be supported by FSCI, it may not be implemented for usage with Serial Manager (FSCI module uses the Serial Manager on top of a serial interface for communication), and you may need to develop your own implementation of I2C.
For more information on FSCI, you can refer to the following documentation (inside KW38 SDK docs folder > docs > wireless > Bluetooth):
- BLE Host Stack FSCI Reference Manual; this reference manual provides a detailed description of the BLE Host Stack serial commands, communication packet structure, and usage of the Framework Serial Communication Interface (FSCI).
- BLE Host Stack FSCI Application Programming; this document provides a description for the Kinetis Wireless Host API implementing the FSCI on a peripheral port such as UART, USB and SPI.
KW38 SDK documentation can be downloaded from the MCUXpresso SDK Builder, after building the SDK and when download dialog is shown:

Regards,
Eduardo.