Americans can now order a second set of free at-home Covid tests from the federal government. Covidtests.gov, the website to sign up for the free tests, launched in January when people could order a maximum of four tests per household. Households that took part in that first round can now order an additional four. Households that missed the first round of test giveaways can order up to eight tests through the website or by calling 1-800-232-0233.