President Trump signed an executive order Wednesday restricting certain categories of immigrants from entering the United States for 60 days, a move he said aims to protect the nation from the coronavirus and jobs for Americans at a time of excessively high unemployment and economic uncertainty.

The White House posted the full proclamation late Wednesday after Trump announced that he had signed it just before the daily coronavirus briefing.

Although Trump had said on Twitter earlier in the week that he was going to suspend all immigration during the pandemic, the order he signed was much less broad and carries several exemptions.

Q: What does Trump’s executive order do?

A: The president suspended the entry of several categories of immigrants for 60 days who are currently outside of the United States and do not already have a valid immigrant visa to travel to this country.

This includes people seeking green cards for work, with some exceptions, as well as the spouses and children of legal permanent residents, also known as green-card holders, and the siblings, parents and adult children of U.S. citizens.

Q: Who is exempt from the order?

A: Foreign nationals who already are in the United States and are applying to become green-card holders are unaffected.

Also exempt are U.S. citizens’ spouses and children under age 21; health-care workers, particularly those fighting the coronavirus; wealthy immigrant investors; members of the U.S. military; special immigrant visa-holders such as Iraqi interpreters for the military; and a broad category of immigrants needed for police investigations or because their entry is broadly considered in the “national interest.”

Spouses and children of exempted groups also are generally allowed to travel with them to the United States.

Existing green-card holders are unaffected.

Q: What are green cards?

A: A “green card” is the more-common term for legal permanent residency in the United States. It is the main path to U.S. citizenship.

More than 1 million green cards are issued each year in the United States, according to the Department of Homeland Security.

Most immigrants, about 700,000 last year, obtain green cards through relatives who are U.S. citizens or to a lesser degree green-card holders. Citizens may apply for parents, spouses and children under 21. They can also apply for siblings and adult children, but that process can take years. Green-card holders may sponsor their spouses and children.

A smaller number, about 139,000 last year, obtain green cards through work, including superstar athletes and highly skilled scientists or laborers. The remainder are for special categories such as U.S. military interpreters in Iraq and Afghanistan, crime victims and unaccompanied minors. Congress created a new category for some Liberian nationals last year. And up to 50,000 green cards are issued in a yearly diversity lottery.

Q: What are the types of immigrants who seek to come live in the United States permanently?

A: Immigrants are people born in a foreign country who come to live in the United States permanently. Most of the 43.7 million foreign-born people in the United States are in the country legally, according to the Census Bureau. Approximately 21 million of them are naturalized U.S. citizens. An estimated 10 million to 11 million more are in the United States illegally, according to the Pew Research Center. The remainder have green cards or another legal status.

Q: Where are they applying for green cards?

A: More than half of all green cards are issued to people already living in the United States, according to DHS.

U.S. Citizenship and Immigration Services, a DHS agency, approved about 577,000 green-card applications last year, most of which went to immigrants who were already living and working in the United States.

The State Department issued more than 460,000 immigrant visas last year, and the majority went to the fiances, spouses, children and other close relatives of U.S. citizens and permanent residents, according to its website.

Q: What are the types of people who seek to come to the United States temporarily?

A: The State Department issued more than 8.7 million “nonimmigrant” visas to people abroad in 2019, according to its website.

Millions of foreign-born people come to the United States every year temporarily, for work, tourism, university studies, business and a host of other reasons. They pick apples in Washington state and strawberries in California, study at Harvard University and the Massachusetts Institute of Technology, and they work as nurses in disadvantaged areas. Others are athletes or entertainers. Often their children and spouses tag along.

In border areas, nonimmigrants include schoolchildren or workers who live in one country and study or work in the other.

Q: Will Trump’s order stop workers from coming to the United States?

A: Yes and no. Trump made clear that there will be several carveouts to allow laborers such as medical professionals to come to the United States. But the Migration Policy Institute estimates that 26,000 would-be green-card holders will be blocked from arriving each month the order is in effect, starting Thursday.

Q: What’s the difference between a “legal” immigrant and an “undocumented” immigrant?

A: An undocumented immigrant is a term used to describe the nearly 11 million people in the United States who do not have legal authority to stay in this country, according to the Pew Research Center.

Some are children, but most are adults working in the United States. Calling them undocumented is a euphemism because such immigrants often have passports from their native country and driver’s licenses in U.S. states that allow it. Some crossed the border illegally to gain entry into the United States. But others applied for visas, underwent background checks and then overstayed those visas.

Legal immigrants have green cards, and those who are naturalized citizens carry U.S. passports. They have undergone background checks, paid fees and met other requirements to remain in the United States.

Q: What is asylum? Why is the United States turning people away who are seeking it?

A: Asylum offers protection to foreigners on U.S. soil if they are eligible for protection under federal law. Asylum seekers must fear persecution in their homelands because of their race, religion, nationality, membership in a particular social group or political opinion.

The United States also offers protection to refugees, those who are fleeing their countries for similar reasons but are applying for protection from abroad.

Both groups are eligible for green cards. But the Trump administration has sought to sharply reduce their numbers, capping refugees at 18,000 this fiscal year, a historic low.

The Trump administration also has all but ended asylum applications at the U.S.-Mexico border after a surge last year. Officials say they have all but closed the border because of the coronavirus and have expelled more than 10,000 asylum seekers in the past several weeks. Democrats have accused the administration of using the pandemic as an excuse to violate asylum law.

Nick Miroff contributed to this report.