Hello @dhruvinrajpura,
You could download the SDK of the MKE14Z256VLH7 microcontroller here. The SDK contains drivers, middleware and example applications to help you with your software development.
Also, if you use or want to use MCUXpresso IDE you could also download the SDK from here:

[MCUXpresso IDE v11.7.0 -> Installed SDKs]
Select the MKE14Z256 microcontroller and install it.

[MCUXpresso IDE v11.7.0 -> Select MCUXpresso SDKs to install]
Click on Import SDK example(s)… and search for KE microcontrollers, choose the frdmke15z which is going to use the SDK_2.x_MKE14Z256 you already install.

[MCUXpresso IDE v11.7.0 -> SDK Import Wizard]
Finally, click Next and a new window with the examples will pop out.

[MCUXpresso IDE v11.7.0 -> SDK Import Wizard -> Examples]
Best regards, Raul.