There is no pdf attachment needed. Go to the rental input and scroll down to the Qualified Business Income Deduction area > Enter the rental number ins the box for "Rental real estate enterprise number if claiming a safe harbor". That will create the election statement, which does not need to be signed.

Here is the help from Lacerte, so ignore the references to screen number and code number

Rental Real Estate Enterprise Number, if Claiming Safe Harbor

Enter the rental real estate enterprise number to claim the safe harbor treatment under Rev. Proc. 2019-38. To be eligible, separate books and records must be maintained for each property, 250 or more hours of rental services must be performed, and the property may not be rented under a triple net lease agreement.