Some details
Office 365 Timesheet by Ignatiuz is an easy-to-use add-in which works with SharePoint 2013, SharePoint 2016 and SharePoint Online (Office 365). It is a productive way of tracking hours spent by your employees on all tasks under different projects within your SharePoint environment.
Employees can track their daily work hours on tasks and projects created by the admin whereas the assigned manager can review and approve the
timesheets submitted by the employees every week. Easy reporting allows managers and administrators to generate and export reports for easier invoicing.