Documentation required for form 8885- Official letter?

Hello!  I chose not to take the advance premium credit and instead to take it on my taxes.  I have to attach documents to form 8453 to prove that I can take this credit.  One of the requirements is: "An official letter reflecting that you were an eligible individual for the months claimed on line 2 in 2020."  Would this be the 1095-A?  Since I didn't get the premiums upfront, Covered California - Obama exchange wouldn't have known if I'm eligible or not.    Maybe I'm misunderstanding something here. Maybe the eligibility is for something else?

Text of the IRS reg:

All health plans.

 

For all health plans, you must include all of the following documents.

  1. An official letter reflecting that you were an eligible individual for the months claimed on line 2 in 2020.

    • For trade-certified individuals demonstrating TAA, ATAA, or RTAA eligibility—A copy of the official letter from the Department of Labor, your state workforce agency, or employment office stating you are eligible for trade adjustment benefits.

    • For PBGC eligibility—A copy of the official letter or a copy of your 2020 Form 1099-R, Distributions From Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, etc., from the PBGC showing you received a benefit paid by the PBGC.