There is a list of countries citizen of which principally do not need visa to enter the Republic of Belarus (see the right-hand column):
https://mfa.gov.by/en/visa/freemove/general/
If not in the list above, for citizen of many countries there is no need for visa to enter the Republic of Belarus via National Airport Minsk, the detailed information is available at: https://mfa.gov.by/en/visa/freemove/airport/
For citizen of Lithuania, Latvia and Poland, there is visa-free ground border crossing according to:
https://gpk.gov.by/peresechenie-granitsy/bezvizovyy-vezd-v-belarus-dlya-grazhdan-litvy-i-latvii/#
If visa is needed, here you can find the information related getting the visa: https://mfa.gov.by/en/visa/oformlenie/