Can somebody tell me how to create Time Start & Time End tracker in Excel with the help of Macro?

I want to create a tracker, in which I can track spending time on all activities done by my employees. For example. If Person A comes at office and start doing his work so he just need click on Time Start icon, which we will create through Macro in Excel, so we can capture the start time and once A will complete his all work, he needs to click on Time End icon and likewise we can also capture the end time. By using this method we can see that how much time time person A spend on a particular activity. Hope this example will help you to understand the question.