I have a script which is in a part, when the part is cloned, it is not working, what should I do?

You need to detect humanoid with FindFirstChild. and use :Connect the :connect is deprecated.

And for clone disable the script of touch, and after clone active this script.

For first, to clone create a RemoteEvent on ReplicatedStorage, now create ServerScript(Script) in ServerScriptService and put this code:

local event = game.ReplicatedStorage.RemoteEvent -- Location of your event

event.OnServerEvent:Connect(function(player,hit,arg) -- On event, get player and mouse hit position and arg
      if arg == "ClonePart" then -- If argument is clone part then
          local try = hit -- Hit position
          local p = game.ReplicatedStorage.Part:Clone()
          p.Parent = workspace
          p.CFrame = try + Vector3.new(0,10,0)   
      end 
end)

Now on LocalScript put this code:

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local event = game.ReplicatedStorage.RemoteEvent -- Location of your event

mouse.Button1Down:Connect(function()
    local try = mouse.Hit
    event:FireServer(try,"ClonePart") -- Send mouse position and argument "ClonePart"
end)

Here is a example of touch:

script.Parent.Touched:Connect(function(hit) -- Changed plr to hit.
	if hit.Parent:FindFirstChild("Humanoid") then -- If find humanoid
		hit.Parent.Humanoid:TakeDamage(10)
	end
end)

FindFirstChild:

Returns the first child of the Instance found with the given name. If no child exists with the given name, this function returns nil. If the optional recursive argument is true, this function searches all descendants rather than only the immediate children of the Instance. Use this function if your code cannot guarantee the existence of an object with a given name.

Hope it helped :D

Wiki pages:

FindFirstChild