Can I add a PDF attachment to a turbotax electronic return? I need to add a 300 page conservation easement appraisal as required by IRS rules.

Unfortunately you cannot add an attachment to an e-filed tax return. TurboTax doesn't provide this feature, in part because the IRS and state e-file systems would not be able to recognize them as a tax form and check their accuracy..

Your best (I think only) choice is to print and file the return by mail, including the attachment and a letter/note explaining why you are sending it.

You could efile your tax return and then submit the appraisal by mail along with form 8453.

Are all taxpayers wishing to do a safe harbor statement for the QBI deduction having to file a paper return? I don't know if you need the statement for each property if you are aggregating as I see Turbo tax is preparing a statement for each property.