System that allows you to communicate transparently with your clients on the progress of their project. Indeed, if the customer has a request, by giving him access to this system, he will be able to create a ticket with his request.
You will then be able to process his request, estimating the time it will take you and possibly ask your questions if necessary. Subsequently, the customer validates or not your timing and you can change the status of the ticket to "to do".
Finally, when his request has been processed, send him a test request so he can validate and say everything is ok! The timing displayed in the ticket will be directly reflected in the ticket statistics. You can organize the tickets as you see fit and create the categories you want.