In the Classic view, you were able to submit and approve timesheets with no tasks or hours.
Is this possible in Modern UX (MUX)?
Release : 16.0.3
Submitting a blank timesheet is not an option in MUX. You will have to add a task.
We suggest creating a custom investment.
Create a new CIT called something similar to 'Miscellaneous Work'. From there you can create an investment, and add staff and tasks to it.