The value-added tax, which is popular in many other countries, would serve as a kind of national sales tax, one that consumers would pay when they make purchases and that businesses would pay for supplies, services and raw materials. A carbon tax would target the emissions of carbon dioxide and other greenhouses gases in the burning of gasoline, coal and other fossil fuels.

The study of the new options — which would represent major changes to American economic policy — comes as the administration looks to tax reform as its next major battleground for implementing its agenda. Trump wants to cut taxes sharply, but his advisers are looking for ways to raise revenue so as not to create a giant hole in the deficit.

Administration officials stressed that no final decision has been made and they are reviewing different alternatives. Two officials and a third person confirmed the consideration of the value-added tax, while one official and the third person confirmed the consideration of the carbon tax.