You have an option to suspend a form until you are ready to lodge it.

Create a form.

Suspended form should show like this -

To track suspended forms -

Navigate to Dashboard , select "Completed". *if the form was suspended after sending for signing, select "To Lodge". 

Filter by Form Type.

Look for the clock symbol.

You will not able to lodge a tax return until it is unsuspended. (Manual press "Unsuspend" to proceed with lodgement).

Please note that it doesn't change ATO due date.

Note, the user may also filter according to "Suspended" via "Dashboard"