All travelers to the US must provide proof of a negative COVID-19 test taken within one (1) day of travel or a positive COVID-19 test accompanied by a letter of verification that isolation requirements have been met. All US travelers must also complete an attestation form which will be provided at the airport.
Please see https://www.cdc.gov/coronavirus/2019-ncov/travelers/testing-international-air-travelers.html for further details on US requirements. Note, all non-US citizens must be vaccinated to enter the US.
Information on COVID-19 testing and TCI COVID-19 testing locations can be found here:
https://www.visittci.com/travel-info/turks-and-caicos-coronavirus-covid-19-testing