Insert into an email message? Probably not, since it isn't a widely used format.

Even TIFF, which has been around forever, has a low level of support.

You can always send it as an attachment, but do make sure your correspondent knows what to do with it.

If in doubt, convert it to something more familiar such as JPEG or PNG.

It is a Nikon RAW file. You cannot expect an email client to display a RAW format image. You need to convert it to a standard image file like a jepg.