Travelers must complete a Public Health Passenger Locator Form. Travelers will receive a confirmation email with their Unique Health Code (UHC) which they will present upon arriving in Rwanda.
Travelers must bring a negative PCR test and will be tested again on arrival. Travelers and airline crew must have a medical certificate with a negative COVID-19 RT-PCR test result issued within 120 hours before their departure. Only RT-PCR tests will be accepted, and the certificate must be clearly marked as such.
Children under the age of 2 are exempt from presenting a COVID-19 test.
Travelers with proof of recovery from the virus within the last 90 days prior to boarding. Proof of a recent positive viral test and a letter from your healthcare provider or a public health official stating that you were cleared to travel.
More info at the CDC site
Travelers who did not get tested, are advised to stay home and self-quarantine for 10 days after travel.