All the production version of the drivers are WHQL signed. However you may need to load a test driver as part of verifying the driver functionality during development. This requires the driver to be test signed. To run a test signed driver in windows requires test signing to be turned on. below is the command to turn on and off test signing.
To turn on loading test signed drivers
Bcdedit.exe –set TESTSIGNING ON
To turn off loading test signed drivers
Bcdedit.exe –set TESTSIGNING OFF