Sitecore not allowing WebP image to attached in an image field. Can anyone suggest how to enable that feature so that we can attached webP format image
WebP format is not (yet) supported in Sitecore out of the box.
Note that WebP format is not supported in all browsers. WebP should really be generated at runtime and cached. Also you need to check the http accept header for "image/webp" to be know if the browser supports it.
You can upgrade Sitecore with the Kam Figy's Dianoga module https://github.com/kamsar/Dianoga in order to support webP. In your media lib, you still upload normal images like jpeg, gif, png. But at runtime they are converted to WebP for supporting browsers.