This view became popular for the first time in 1817 by the economist David Ricardo in his book On the Principles of Political Economy and Taxation. He argued that free trade broadens diversity and reduces the prices of goods available in a nation, while making a better exploit of its own resources, knowledge and specialized skills. A free trade agreement (FTA) is an agreement between two or more countries to facilitate trade and remove trade barriers. The aim is to eliminate tariffs completely from day one or over a number of years. A trade agreement signed between more than two parties (usually neighbouring or in the same region) is considered multilateral. They face the main obstacles – to content negotiation and implementation. The more countries involved, the more difficult it is to achieve mutual satisfaction. Once this type of trade agreement is governed, it will become a very powerful agreement. The larger the GDP of the signatories, the greater the impact on other global trade relations. The largest multilateral trade agreement is the North American Free Trade Agreement between the United States, Canada and Mexico.  For example, a nation could allow free trade with another nation, with exceptions that prohibit the importation of certain drugs that are not authorized by its regulators, or animals that have not been vaccinated or processed foods that do not meet their standards.
The benefits of free trade were outlined in On the Principles of Political Economy and Taxation, published in 1817 by economist David Ricardo. A free trade agreement is a pact between two or more nations to reduce barriers to trade between imports and exports. Under a free trade policy, goods and services can be bought and sold across international borders without government tariffs, quotas, subsidies or bans. For most countries, international trade is governed by unilateral trade barriers of various kinds, including tariffs, non-tariff barriers and absolute prohibitions. Trade agreements are a way to reduce these barriers and thus open up the benefits of enhanced trade to all parties. The nearest countries tend to trade more, particularly with goods, and this is the case in the UK and the EU. There are a large number of trade agreements; some are quite complex (the European Union), while others are less intense (North American free trade agreement).  The resulting level of economic integration depends on the specific type of trade pacts and policies adopted by the trade bloc: a trade agreement (also known as the trade pact) is a large-scale tax, customs and trade agreement, often with investment guarantees.
It exists when two or more countries agree on conditions that help them trade with each other. The most frequent trade agreements are preferential and free trade regimes to reduce (or remove) tariffs, quotas and other trade restrictions imposed on intermediaries.