Use CFrame.lookAt()
You can use CFrame.new() or CFrame.lookAt() this way:
-- Assuming you are running the code on a localscript:
local Character = game:GetService('Players').LocalPlayer.Character
local Root = Character.HumanoidRootPart
local Object_to_Look = workspace.Part -- change this to whatever you want
Root.CFrame = CFrame.new(Root.Position, Object_to_Look.Position)