I have observed some tool on Xcode. This is shown in screenshot. These tools are visible at times. I would like to know there use and when does these appear?
Those are Mac UI controls. You would use them if you were writing a Mac GUI app. Create a Cocoa application project and use the controls to build your user interface.
I'm guessing you're doing iOS development or else you would not find the controls strange. I have no idea why the Mac UI controls would show up in an iOS project. Don't use those controls for iOS apps.