See the ATO website for:
You can attach an Interposed Entity Election or Revocation (Schedule Y) to the return and lodge it using PLS by selecting it from the Preparation > Schedule menu.
A Standalone Interposed Entity Election (Schedule YY) may be prepared and lodged separately from the Partnership return.
The item and labels are listed for data entry on a set of tab cards:
Standalone forms associated with partnerships. These forms are lodged separately from the partnership return;
Worksheets that support the return but do not generate lodgable attachments are: