Each U.S. household is eligible to receive four free tests as of Sept. 25, according to a news release from the U.S. Department of Health and Human Services. Orders can be placed at COVID.gov/tests.

HHS announced last week it would invest $600 million in 12 domestic COVID test manufacturers—Access Bio in New Jersey; Advin, CorDx, iHealth, Quidel, and Kwell Laboratories in California; Azure in Texas; InBios in Washington; Maxim Bio in Maryland; OraSure Technologies in Pennsylvania; Princeton BioMeditech in New Jersey; and Sekisui in Delaware—ahead of the program’s relaunch.

The move reduces reliance on overseas manufacturing and will “help mitigate the spread of the virus,” HHS Secretary Xavier Becerra said in the release. 

The wave of free tests is being released ahead of holiday travel and gatherings, according to COVID.gov. Already, domestic COVID infections are hovering near levels of the pandemic’s first peak in 2020, and approaching the Delta peak of late 2021, according to wastewater surveillance and modeling by forecasters. 

While infection rates are dropping slightly, according to wastewater data from federal contractor Biobot Analytics, they’ll likely surge again “later this fall into winter,” Jay Weiland, a leading COVID modeler, tells Fortune—perhaps repeatedly, with lulls in between.

CDC updated data added to the model.

Seems to be riding the top of the range at the moment, but I believe it will trend towards the midpoint in the next couple of weeks. https://t.co/MLnQqi9J3U pic.twitter.com/nezJvOEg4N

— JWeiland (@JPWeiland) September 21, 2023

For those looking to get their hands on a set of free tests this fall, here are some commonly asked questions and answers.

Where can I order free COVID tests in the U.S.?

Simply visit COVID.gov/tests to place your order.

What information do I need to order?

Just your name and mailing address. PO boxes are okay if they’ve been registered as residential.

You don’t need your ID, credit card, or health insurance information. 

Note that all U.S. residential addresses are eligible, including those in Alaska, Hawaii, Puerto Rico, U.S. territories, and at overseas military and diplomatic addresses like APO, FPO, and DPO.

What if I can’t order online?

If you don’t have internet access or are having issues placing your order, you can call 1-880-232-0233 (1-888-720-7489 TTY) and receive help in English, Spanish, or more than 150 additional languages from 8 a.m.–midnight ET, seven days a week.

People with disabilities can get help placing their orders by calling 1-888-677-1199, Monday through Friday, 9 a.m.–8 p.m. ET. Or they can email DIAL@usaginganddisability.org.

Those who are blind or low-vision can receive 12 at-home tests approved for the visually impaired, while supplies last. The tests require a compatible Bluetooth-enabled smartphone and an app that can be downloaded from the App Store for iOS or Google Play for Android. Orders can be placed here and will ship the week of Oct. 2.

How quickly will the tests be sent?

Tests will be mailed via the United States Postal Service’s priority mail, which typically takes one to three business days to arrive. If you provide an email address when you place your order, you’ll get an estimated delivery date and tracking number for use on USPS.com.

What if my tests are expired?

If you’re looking to do a bit of autumn purging, think twice before chucking expired tests, COVID.gov advises. Many manufacturers have extended expiration dates, including Abbott, iHealth Labs, and Pfizer. The U.S. Food and Drug Administration offers a full list of manufacturers that have extended their expiration dates, and to when, by test name.

Do COVID tests still work on currently circulating variants?

Yes, according to the HHS. At-home COVID tests “work as well as they always have”—even on new variants like “Pirola” BA.2.86, “Eris” EG.5.1, and “Fornax” FL.1.5.1, Dr. Amesh Adalja, an infectious disease specialist and senior scholar at the Johns Hopkins Center for Health Security, recently told Fortune. 

If you have COVID symptoms and have tested negative, you may have another respiratory virus. Or you may have tested too early or performed the test wrong.

At-home COVID tests not working is a common complaint these days, Raj Rajnarayanan—assistant dean of research and associate professor at the New York Institute of Technology campus in Jonesboro, Ark., and a top COVID variant tracker—recently told Fortune.

In such cases, the problem is usually that the sick individual tested too early. At the end of an infection and especially at the beginning, viral loads are not always large enough to turn a test positive.

Most people with symptoms who test negative initially “test positive after a day or two,” Rajnarayanan said.

Here are some additional tips for testing, from the U.S. Centers for Disease Control and Prevention:

• If you have COVID symptoms, test immediately.
• If you test negative using an at-home test, repeat the test again in 48 hours.
• If you were exposed to COVID, test at least five full days after exposure.
• If you test negative using an at-home test, repeat the test again in 48 hours.
• If you still test negative, wait 48 more hours and test for a final time.
• In both cases, if you’d rather not wait, you can obtain a PCR, or polymerase chain reaction, test at a doctor’s office. These are more sensitive and tend to be more accurate.