Very short letter only a few lines long.
To Whom It May Concern,
XXXX was seen in my office on XX/XX/XXXX via tele visit. He tested positive for Covid on XX/XX/XXXX. Took Paxlovid for treatment. Recovered well from Covid. It is my medical opinion that XXXX may travel without at restrictions.
Signed by doctor.
They posted it in his MyChart account online so he could print it out for travel.