All countries can receive a visa on entry to Rwanda – you can pay in USD or with a Credit Card. Immigration link and further information is here.
COVID – From Aug 2020 international arrivals are required to have a COVID test within 72 hours of arrival. Once you land you will receive another test at the airport. If negative you will be able to proceed without any other restrictions. If positive then you will be required to quarantine in a Govt nominated hotel – you will be required to pay for the cost of the hotel.