Transfer to / from the airport
The Minsk National Airport is 25 miles (40 km) away from the city.
Option 1: You can get to / from the city by bus or by shuttle bus that runs every 20-30 minutes and arrives at the Central Bus Station. The ticket cost is around €2. The trip takes about an hour.
Option 2: Use taxi. General advise is to use taxi called Pyatnica (Taxi5). It is an elegant service, a bit more expensive than others, however having drivers wearing suits, good & clean cars, free wifi & chargers. You can also pay via your credit card. The cost of getting to/from the city is fixed there and is 44 BYN (~$20).
The cheaper alternative to Pyatnica is Yandex.Taxi (Android, iOS). The cost of the trip is not fixed and is around 30 - 40 BYN ($15 - $20).
General advise is try to avoid ordering a taxi not using the apps, because there is a little chance that you'll be charged unreasonably high price.