Missing "Digital ID" option in Apple Wallet for passport

I'm trying to add my U.S. passport to my Apple wallet on my iPhone 16 Pro running iOS V18.7.2. The instructions say to:

1. Open Apple Wallet - no problem.
2. Tap add ( the + sign) - no problem.
3. Tap on "Driver's License and ID Cards" - no problem.
4. Then Tap "Digital ID" - PROBLEM!!!

On my phone there is no "Digital ID" option under Driver's License and ID Cards.

What am I missing?

I was able to add my New Mexico drivers license with no problem.

Thanks in advance for any help/insight on this.