This tutorial provides the steps for excluding folders from Spotlight search on Mac System. This is useful when you have private information in certain folders and don’t want it to appear when any user does a Spotlight search.
Click the Apple icon and select System Preferences from the list of menus.
In the System Preferences window, navigate to Personal section and click the Spotlight option
In the Spotlight Preferences window navigate to Privacy tab.
Click the + sign to launch and select the location you want to exclude from Spotlight search.
In the above screenshot, Downloads folder has been added and this will Prevent Spotlight from searching this location.