Show/hide Solution and Advanced Build Configurations

To enable solution and advanced build configurations go to Tools -> Options -> Project and Solutions -> General
and check "Always show solution" and "Show advanced build configurations"

 


If you want the drop-downs with 'Debug' and 'Any CPU' in the Standard toolbar. Then right-click on the Toolbar -> Customize -> Commands tab -> Build section and drag 'Solution Configurations' and 'Solution Platforms' to the toolbar.




Now you see the standard toolbar as below