Armenia allows citizens of specific countries and territories to visit Armenia for tourism or business purposes:
- without having to obtain a visa or
- allows them to obtain a visa on arrival or online
- for some countries the visa requirement waiver is practiced on ad hoc basis, and is not formalized by a bilateral agreement.
Holders of all types of passports from United States and all European Union / EFTA citizens are not required to obtain a visa for entry to Armenia.
Citizens of foreign countries for whom a visa-free regime is set can stay on the territory of the Republic of Armenia for no more than 180 days during one year if no other term is defined by the international agreements of the Republic of Armenia.
More details you can find on the website of the Armenian Ministry of Foreign Affairs.