Nikon NIKKOR Z 70-200mm f/2.8 VR S Lens - Manual (Page 129)

105 The i Button
A
NEF (RAW)
NEF (RAW) image files (extension “*.nef”) contain the raw data output
from the image sensor. Using Nikon’s ViewNX-i or Capture NX-D
software, you can adjust and re-adjust settings such as exposure
compensation and white balance as often as you please without
degrading image quality, making this format ideal for photos that will
be processed in multiple different ways. ViewNX-i and Capture NX-D
are available free-of-charge from the Nikon Download Center.
The process of converting NEF (RAW) images to other formats is
referred to as “NEF (RAW) processing”. You can save NEF (RAW) images
in other formats using the ViewNX-i and Capture NX-D computer
applications or the
NEF (RAW) processing option in the camera
retouch menu.