How to emphasize whites tones?

https://forums.adobe.com/people/media+kat  wrote How would you emphasize the white tones from a dress in LR so maybe only whites and darks are emphasized and other tones are less saturated?

The camera profile has the most impact on image rendering so start there FIRST. To emphasize detail in the whites (highlights) and darks (shadows) use a profile that has lower contrast such as Camera Faithful, Neutral, or Flat. Next as suggested by cmgap apply -Highlights and +Shadows using equal but opposite settings such a -50 Highlights and +50 Shadows. Try different settings keeping them equal but opposite until you reveal the desired detail in the white dresses and shadows. Then adjust the other controls for proper midtone Exposures & Contrast and set the Whites and Blacks clipping points (hold the ALT key). To achieve even more detail in the white dresses try adding a small amount of Dehaze (+15 to 25).

Try sliding the Highlight control to the left. If there is data that can be pulled up this is one tool that will do that. After you experiment with the Highlights, try adjusting the 'Whites' Slider and maybe a bit of Exposure. If it is looking to dark you can try sliding the shadow control to bring out more details. You might to try the Clarity slider just a bit to bring up some contrast in the mid-tones.

Oh and just for fun, create a virtual copy and try the Auto feature - you can compare the Auto feature with your adjustments.

Post an image here that is representative of what you're working with and likely a few of us can show you different approaches to what I've mentioned.

White is white!  and not a lot more you can do about those tones.

The fun part about editing is then using Saturation,  Exposure, Contrast, especially the HSL panel, Split Toning, etc, to visually create the effect you want, either by Global or Local adjustments.

If you find a Preset that achieves near to your want, apply it to one photo and observe all the Develop adjustments to learn what it has changed, then modify the Preset if needed. And with v7.3 you have the new Creative Profiles to start the process..