What tax document do I need to share with health insurance?

I am looking to get health insurance through Aetna to cover a inpatient mental health stay (one at a hospital, and the other at a retreat center) that I had 5-6 months ago. I am looking to get retrospective preauthorization and claim coverage for this. I did not have health insurance at the time of my hospitalization and also had not filed my 2022 taxes. I was told by a family member that’s helping me get an insurance broker that I needed to get my taxes done, and present the information to the health insurer so that I could get covered. Well I got my taxes done and sent off to the IRS 2-3 weeks ago.

So, what do I do now? Does the IRS send me a letter confirming all this, and then I present it to Aetna? Anything I should know, please disclose, things like terms and such. Is it a retrospective review that I’m looking to get? I have not received any notice or bill from the hospital, but the finance department at the retreat center seemed pretty urgent when I called them a few months ago (but they haven’t been calling me up).

\What are my chances of getting this sorted out? I feel like I am coming up on a deadline of 6 months since my hospitalization.