Hi Rodrigo,
Welcome to Clockify forum!
Making a project private/public refers to who can track time on that project (who can select it in the project picker when tracking time).
By default, all users will be able to see other users’ time entries in Report including those tracked on private projects.
You can change this and set if you want Regular users to see only their own time, on public projects, or all time entries.
This is an extra feature available on our paid plans, and you can learn more about it here.