A tariff is a tax or duty imposed by a government on goods (not services, generally) brought into a country. The importing business pays this duty to its government. The business may then pass this cost on to the customer, even if there is a contract in place with an agreed upon price (treated in the contract as an unforeseen condition). The price for the item may increase without notice or the vendor may list an additional importation cost on an invoice.
The federal administration announced reciprocal tariffs which impose a baseline tariff of 10 percent on all imports, effective April 5. A second layer of country-specific tariffs were supposed to take effect on April 9 but were paused temporarily.
For best practices and guidance, please use this link for information on tariffs.