Safari web browser can be made as default web browser in a Windows PC using the General Settings –> Preferences menu. This can be done by clicking the General Settings menu available at the top right corner and selecting Preferences from the list of available menus.
In the General Preferences, navigate to default web browser and click the drop down. This would display the list of web browsers available on the system. Now to make Safari as the default browser, select Safari from the drop down values.
Click the close button available at the top right corner of the General Preferences window to apply this change.