Selective color is maybe a not done but sometimes it gives a nice effect. So why not? One way to do it is using a Black and white adjustment layer in Photoshop and using the mask. But we can also do it in Lightroom. Start with opening your image in Lightroom
Do your regular workflow
Then we go to HSL Panel in Photoshop. Here we remove all colors except the reds and oranges. But that depends on your image.
In the picture we see the truck is very red but there is some color in the background. We can remove this with the brush. So grap a brush and desaturate the background (flow and density of the brush 100%)
The red color is the mask and that are the areas I changed into black and white.
If you send your work to client and you don't want that the can edit it or print it, before the have paid, here is a solution. Save your image as a .PDF and secure it with a password. Go to File > Save and choose Photoshop PDF and hit the 'Save' button.
Then go the security. Here you can choose for the option to add a password. So hit the checkbox, add the password and click on 'Save PDF'