https://www.adobe.com/in/creativecloud/photography/discover/duotone-effect.html
Make a duotone effect in 4 steps in Photoshop | Adobe
Use a Gradient Map adjustment layer to add duotone-inspired colour effects to a photo in Adobe Photoshop.
make aduotone effectstepsphotoshopadobe
https://www.luxa.org/image/duotone
Duotone Image Effect Generator
Apply duotone color effects to photos with custom shadow and highlight colors
image effectduotonegenerator