There is this error that I cant fix how do I fix it? I'm trying to make a sprint script.

Try this

Add a LocalScript to StarterCharacterScripts

Use this code

local userInputService = game:GetService("UserInputService")
local humanoid = script.Parent:FindFirstChild("Humanoid")

local sprinting = false

userInputService.InputBegan:Connect(function(key)
    if key.KeyCode == Enum.KeyCode.LeftShift then

        if sprinting == false then
            sprinting = true

            humanoid.WalkSpeed = 32

        else

            sprinting = false

            humanoid.WalkSpeed = 16

        end

    end
end)

Whenever the error mentions "<eof>", it's because you forgot an end somewhere (or, in this case, three of them). If you keep up consistent indentation, it makes it easier to find - whenever you have a double-unindent, there's a problem.

Also, you should almost never connect to events inside other events!

local UserInputService = game:GetService("UserInputService")
local player = game.Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local humanoid = character:WaitForChild("Humanoid")

UserInputService.InputBegan:Connect(function(input, gameProcessed)
    if gameProcessed then return end
    if input.KeyCode == Enum.KeyCode.LeftShift then
        humanoid.WalkSpeed = 90
    end
end)
UserInputService.InputEnded:Connect(function(input, gameProcessed)
    if gameProcessed then return end
    if input.KeyCode == Enum.KeyCode.LeftShift then
        humanoid.WalkSpeed = 16
    end
end)

Modifications:

• Reference humanoid once outside of the events for simplicity (I assume this is a StarterCharacterScript)
• Respect gameProcessed (or else when the user is chatting and presses shift or other controls you'll process them instead of correctly ignoring them)
• InputEnded is connected to once, not each time the user presses a key
• It's WalkSpeed not CharacterWalkSpeed