What a tariff is
A tariff is a tax levied on goods imported from another country. Despite the common political framing, the exporting country does not pay the tariff — the importing company pays it to its own government when the goods cross the border. Who ultimately bears the economic cost depends on market conditions.
Who pays in practice
For goods where the importing country has market power, some of the tariff may be absorbed in lower export prices. For goods where the exporting country has market power, the cost falls almost entirely on the importing country's consumers and businesses. Studies of US tariffs on Chinese goods found that the majority of costs were borne by US consumers and businesses.
Second-order effects
Protecting one domestic industry with tariffs raises costs for other industries that use that product as an input. US steel tariffs raised costs for US car manufacturers, construction companies and appliance makers — industries that employ far more people than the steel industry. The net employment effect of tariffs is therefore complex, not the simple story that is often presented.