Hi,

Timesheets app:

Record the time spent by an employee on a project. Timesheets are a method of tracking employee working time. With this Timesheets feature in Odoo, one can easily analyse the employee working report, says the project-based working time and task-based working time.

Planning app:

The planning module of Odoo operates based on calendar operations. In that user can configure the schedule of operations of a task or an associated project using the time and its functionality.

Hope it helps