so no tax money goes to post office, is it funded from stamps and delivery fees?

edit:

Overview The U.S. Postal Service (USPS) generates nearly all of its funding—about $78.5 billion annually according to the USPS’s most recent financial report—by charging users of the mail for the costs of the services it provides. Congress, however, does provide an annual appropriation—about $50 million in FY2023—to compensate the USPS for revenue it forgoes in providing free mailing privileges to the blind and overseas voters.

FY2024 U.S. Postal Service Appropriations