Hello and welcome to Windows Central.
Were you referring to the Start Screen/Menu instead, not the traditional Desktop? You may not have deleted it - this is impossible to do - though you may have "unpinned" it. If so, in your Start Menu/Screen, click on "All Apps", then find "People" listed under "P". Right click on that and select "Pin to Start". That should pin the People Tile back to the Start Screen.
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