Americans will be able to start ordering free at-home COVID-19 rapid tests starting on January 19, the White House said Friday.

President Joe Biden said earlier this week that his administration is purchasing 1 billion at-home rapid tests to distribute to the American public free of charge. The first 500 million of those tests will be made available for American families to order next week.

At the beginning, residential addresses will be limited to ordering four tests. The limit will be in place in order to “promote broad access” to the free tests, according to a White House fact sheet.

The tests will be available for order through COVIDTests.gov. The White House will also be offering a call line free of charge for Americans who are unable to order tests online, officials said.

Ordered tests will be delivered by mail in partnership with the U.S. Postal Service. Officials said ordered tests are expected to ship between seven and 12 days after orders are placed.

News of the option to order free at-home tests came days after the Biden administration said private health insurance companies will be required to cover the costs of over-the-counter at-home COVID-19 tests starting Saturday. Insurance companies will be required to cover up to eight at-home tests per covered individual every month, administration officials said.

The White House pointed to testing as “an important tool” in slowing the spread of COVID-19 and noted that, in addition to at-home testing options, there are also more than 20,000 free testing sites operating around the country.

New virus infections have spiked over the last two months due in part to the spread of the Omicron variant, which the World Health Organization identified as a “variant of concern” in late November. The Omicron variant was first reported in the U.S. in early December and quickly spread through all 50 states.

Public health officials have encouraged Americans to seek out COVID-19 tests if they suspect they are experiencing virus symptoms within five days of being exposed to someone known to have tested positive.

Following the rise of new cases reported after the holidays as the Omicron variant continued spreading, many Americans throughout the U.S. have reported difficulty in accessing COVID-19 tests, with some individuals waiting in line for hours at in-person testing sites while pharmacies’ supplies of at-home rapid tests dwindled.

The White House said administration officials have “taken significant action” to enhance testing access since the start of the year and said the number of at-home tests available to Americans during the second half of 2021 had jumped from 24 million to more than 300 million between August and December.

In January, “the number of at-home, rapid tests available to the U.S. market will rise to 375 million—in addition to the free tests available through COVIDTests.gov,” the White House said.