Making a "Fireball" do damage when it hits an enemy or player?!

I'm making a script where you launch a "Fireball" from a tool. But, what I want the "Fireball" to do damage to enemy monsters or players. I'm sending a script in Repliacted Storage and cloning that script into the fireball and using the On Touch command to make the fire ball do damage.

Here is the script in the tool

local Plr = game:GetService("Players").LocalPlayer
local tool = script.Parent
local FireBallAttack = game.ReplicatedStorage:WaitForChild("FireBallCollisions")
local Ammo = 5

	tool.Activated:connect(function(Player)
	
 	local FireBall = Instance.new("Part")
    FireBall.Shape = "Ball"
    FireBall.BrickColor = BrickColor.new("Maroon")
    FireBall.Transparency = 0.5
    FireBall.TopSurface = "Smooth"
    FireBall.BottomSurface = "Smooth"
    local Fire = Instance.new("Fire")
    Fire.Parent = FireBall
    FireBall.CFrame = Plr.Character.HumanoidRootPart.CFrame * CFrame.new(0,0,-6)    
    local BodyVelocity = Instance.new("BodyVelocity")
    BodyVelocity.Velocity = Plr.Character.HumanoidRootPart.CFrame.LookVector * 90
    BodyVelocity.MaxForce = Vector3.new(math.huge, math.huge, math.huge)
    BodyVelocity.Parent = FireBall
    local Explosion = Instance.new("Explosion")
    --create touched event
    FireBall.Touched:Connect(function(hit)
        wait()
        FireBall:Destroy()
    end)
    FireBall.Parent = workspace
    --Add Fireball to debris (will be destroyed after 60 seconds)
    game:GetService("Debris"):AddItem(FireBall,10)

local ClonedFireBallAttck = FireBallAttack:Clone()
ClonedFireBallAttck.Parent = FireBall
	
	Ammo = Ammo - 1 

print(Ammo)
if Ammo == 0 then 
	script.Parent:Destroy()
end


end)

And now here's the script in Replicated Storage

function OnTouch(hit)
	if script.Parent.hit:FindFirstChild("Humanoid") then
		local Humanoid = script.Parent.hit:FindFirstChild("Humanoid")
		Humanoid.Health = Humanoid.Health - 20
	end
end

script.Parent.Touched:Connect(OnTouch()

It should be if hit.Parent:FindFirstChild("Humanoid"), and you should also use hit.Parent.Humanoid:TakeDamage(20) instead of subtracting health, although they are pretty much the same ig

One thing is that instead of doing-

Humanoid.Health = Humanoid.Health - 20

You can write-

Humanoid:TakeDamage(20)

and like iXBruv said, I think you might wanna make (OnTouch() be (OnTouch)