There are three e-visa types for people traveling to the Republic of Kenya temporarily:
Single Entry visa
Issued for single entry to persons whose nationalities require a visa to enter Kenya either for business, tourism or medical reasons.
Issued to persons connecting through Kenya to other destinations for a period not exceeding 72 hours. Those connecting flights directly without leaving the airport don't need to apply for Transit visas.
Issued to Diplomatic, Official and Service passport holders coming into the country on official duties, or transiting through Kenya to a third country for official business or duties. It is also issued to government officials and dignitaries on official duties but holding ordinary passports. It is issued free of charge / gratis.