How can I scale web content to make it larger or smaller?

You can make web content appear larger or smaller by changing the webview's resolution, which is the number of web pixels per Unity unit. If you're using one of the prefabs (WebViewPrefab or CanvasWebViewPrefab), you can change the resolution by changing the prefab's Initial Resolution property.

WebViewPrefab's Initial Resolution property

Decreasing the resolution makes web content appear larger and increasing the resolution makes content appear smaller. You can also change the resolution programmatically at runtime by calling IWebView.SetResolution().