zistemo allows you to add tasks and subtasks to Projects/Invoices/Estimates as well as show them in Reports.
On the Project page, first, you should choose the “head task”, then click on the ‘subtasks’ button:
Enter a name for this group of tasks and add a description (optional), then click on the “Save” button:
Now you can add subtasks to this group:
On the timesheet table, project members will be able to log hours to tasks and group’s subtasks but not to the groups:
When you will generate an Invoice based on this project, the invoice will show information on each of the tasks, subtasks and subtasks groups totals, as you can see below:
If you want to create groups and subtasks right on the Invoice/Estimate, you can do so by adding ‘subtotals lines’ (more here).
As for the Reports (Timesheet Details, User Summary, Tasks Invoiced, Project Summary, Project Hour Report, Project Hours, Task Summary), the subtasks will be displayed like this: