Hi Shiv Aishwarya,
Please refer: How To Sucessfully Program a Custom made Kinetis Microcontroller Board.
Since you are using the MCUXpresso IDE, step8 be replaced by resurrect locked Kinetis device in GUI Flash Tool.
The GUI Flash Tool previously was only for the LinkServer (or LPC-Link2) connections.

GUI Flash Tool
Now it supports all debug probe connections, including P&E and SEGGER, and I can program, erase or even resurrect a ‘bricked’ Kinetis device:

LinkServer GUI Flash Tool

PEMicro GUI Flash Tool

Segger GUI Flash Tool
Using the toolbar icon is probably the most convenient way to use the GUI Flash Programmer, it is possible to run it from the debugger launch configuration too:

Running GUI Flash Programmer from Launch Configuration
The operation executed is logged in the Console View:

GUI Flash Tool Console Output
Best Regards,
Robin
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