International travel to Belarus is only allowed for "essential reasons". This does not apply to nationals and residents.
There are exemptions to the closure of the border for essential reasons, including travel for compelling family reasons. Tourist trips are not allowed. You can find a full list of exemptions at https://gpk.gov.by/covid-19/
Non-resident foreign travelers must have valid medical insurance with a minimum medical coverage of € 10,000 EUR. Insurance must provide full coverage of all costs of COVID-19 treatment. Proof of this insurance must be provided during the visa application process, or upon arrival at Minsk airport if traveling under the visa-free regime.
Travelers who present a valid international certificate for full vaccination against COVID-19, using an approved vaccine, are exempt from the testing and quarantine requirements. The final dose must have been administered between 1 and 12 months prior to arrival.
Travelers must be quarantined for 7 days upon arrival.
Upon arrival, proof of a negative PCR test must be presented, taken within the previous 72 hours. The certificate must be printed in Belarusian, Russian or English. This does not apply to nationals and residents of Belarus.
For more details State Border Committee, Belarus