I did a word search for "attach" in the 172 instructions.  On Page 3, it says:

Deducting a Carryforward
If you carry forward your NOL to a tax year after the NOL year,
list your NOL deduction as a negative figure on Schedule 1
(Form 1040) for the year to which the NOL is carried. Estates
and trusts, include an NOL deduction on Form 1041.
Attach a Form 172 for each NOL to your Form 1040 or Form
1041 if it applies.

I would file a paper return if I didn't want to wait, but I get the impression that a lot of preparers these days don't even have an office printer.