Anyone can help my make a coin that gives 10 extra max health?

100 health is automatic set I don't think you can give more than 100. Unless if the player is already harmed. Though you could change how much health something takes.

Please note that this isn't a website to be asking for scripts/code.

Anyways it's fairly simple to make this type of script, first of all make sure to have a server script in Workspace or ServerScriptService and not a module/local script, then have a part in Workspace that will work as a coin.

local coin = game.Workspace.Coin -- The coin that will give +10 extra hp.
local debounce = false -- Making a debounce so that the coin function doesn't fire too many times. (Cooldown)
local debounceTime = 5 -- Time for the debounce (seconds), can be changed.

coin.Touched:Connect(function(hit) -- Function that fires every time the coin gets touched.

    if hit.Parent:FindFirstChild("Humanoid") and debounce == false then -- If the object that touched the coin has a Humanoid in it the block of code will run.
        local humanoid = hit.Parent:FindFirstChild("Humanoid") -- Making the humanoid a variable.
        debounce = true -- Starting the cooldown

        humanoid.MaxHealth = humanoid.MaxHealth + 10 -- Giving the Humanoid's max health + 10 health

        wait(debounceTime) -- The amount of time this block of code can be run again.
        debounce = false -- After the debounce time has ran out the debounce has been set to false meaning this block of code can be run again.
    end

end)