What does the letter of recovery need to say?

I have no direct knowledge about this subject, but it wouldn't hurt (and might be helpful) to include your passport number.

CDC site. What if I've recently recovered from Covid?

https://www.cdc.gov/coronavirus/2019-ncov/travelers/testing-international-air-travelers.html#:~:text=If%20you%20recently%20recovered%20from,provider%20or%20a%20public%20health

People who have recovered from COVID-19 can continue to test positive for up to 3 months after their infection. CDC does not recommend retesting within 3 months after a person with COVID-19 first developed symptoms of COVID-19 (or the date their sample was taken for their first positive viral diagnostic test if their infection was asymptomatic).

If you have had a positive viral test on a sample taken during the past 90 days, and you have met the criteria to travel, you may travel instead with your positive viral test results and a signed letter from a licensed healthcare provider or a public health official that states you have been cleared for travel according to CDC’s travel guidance. The positive test result and letter together are referred to as “documentation of recovery.”

A letter from your healthcare provider or a public health official that clears you to travel, must have information that identifies you personally (e.g., name and date of birth) that matches the personal identifiers on your passport or other travel documents. The letter must be signed and dated on official letterhead that contains the name, address, and phone number of the healthcare provider or public health official who signed the letter.

Does anybody know how this "documentation" works if the positive test result (two tests showed positive) were from home tests?

I can get the document of recovery from my Dr., but I don't know how to document the result of the tests.

I followed that up with a telehealth visit with my doctors' office.

I think the strategy is that if you test positive from a home test, you should immediately get an official proctored test, so you have documentation to start the clock on your recovery.

Thank you!

Yes you need to get an "official" positive test not just a self-administered at home test - so either tele-health or in person.