Ok so, you will need to add a LocalScript into StarterPlayerScripts and here is the code. This is compatible for mobile and computer:
local UserInputService = game:GetService("UserInputService")
local ContextActionService = game:GetService("ContextActionService")
local Players = game:GetService("Players")
local Camera = workspace.CurrentCamera
local Player = Players.LocalPlayer
local function CameraControl(ActionName, InputState, InputObject)
if InputState == Enum.UserInputState.Begin then
Player.CameraMode = Enum.CameraMode.LockFirstPerson
UserInputService.MouseBehavior = Enum.MouseBehavior.LockCenter
ContextActionService:UnbindAction("CameraControl")
end
end
ContextActionService:BindAction("CameraControl", CameraControl, false, Enum.UserInputType.MouseMovement, Enum.UserInputType.Touch)