Note: Advice in this article will only work for DotNetBrowser 1.
See the corresponding article for DotNetBrowser 2 here.

DotNetBrowser recognizes the device scale factor that is used in the environments with HiDPI displays and renders HTML content with respect to that scale factor. The BrowserView control is compatible with different DPI awareness modes starting from version 1.16. The DotNetBrowser UI components get the DPI awareness settings from the application configuration where it's used and configure Chromium processes to use the same DPI awareness mode.

Note: Take into account that DotNetBrowser supports High DPI only if your .NET desktop application supports it.

These MSDN articles describe how to create DPI-aware .NET desktop applications: