The Immediate window is used to debug and evaluate expressions, execute statements, print variable values etc.The Immediate window also supports IntelliSense.There are different methods to open Immediate window.
Method 1 : -
We can open Immediate Window from debug menu.
Some times Immediate Window menu would be missing.If it seems to be missing for you then you can get the Immediate Window menu by going to Tools->Customize and then select the Commands tab, choose for Debug commands and drag Immediate onto the toolbar.Read more about this issue here.
Method 2 : -
Use the Keyboard Shortcut keys Ctrl+Alt+I
Method 3 : -
We can also open Immediate Window through VS Command window.Just type “immed” in the prompt and hit enter Immediate Window will open.
For more details about Immediate Window go to MSDN Link