How can i make an button that if you press will add one point to the text?

Here is a way to do it using remoteFunctions.

You will create the remotefunction on the server with a certain name, then get it on the client in a localscript. Then you call it; when the server receives the call request, it checks if it's already been called. If so, it does nothing, but if this call is the first, it takes action.

The server returns the status of the call.

in a modulescript in serverScriptStorage:

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local clickRequest = Instance.new("RemoteFunction")
clickRequest.Parent = ReplicatedStorage
clickRequest.Name = "ClickRequest "

local hasBeenIncremented = false
local count = 0
local incrementerUserId = nil

local function onClickRequest (player)
    print(player.Name, "wants to increment the number")
        if hasBeenIncremented then
            return false --it has already been incremented by someone else
        end
        --actually increment the number
        incrementerUserId = player.UserId
        hasBeenIncremented=true
        count = count + 1
        --take other actions which you want to sync to servers - updating physical world, sending messages etc.
    return true
end

clickRequest .OnServerInvoke = onClickRequest Requested

in a localscript inside the player object

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local clickRequest = ReplicatedStorage:WaitForChild("ClickRequest ")

local IWasFirst = clickRequest:InvokeServer()
print("I tried to click; was I first?"..tostring(IWasFirst))

game.somewhere.MouseButton1Click:connect(function() some variable = variable + number end) Then self destruct the point script.