Russian visas must be obtained before arriving in Russia. I also advise you to visit the Russian visa service. After receiving the issued tourist visa, you will be able to enter and leave Russia within the period specified in your visa, up to 3 months without any extension, unless otherwise agreed by the immigration officers at the ports of entry. Without a valid visa, you cannot travel outside the transit zone of Moscow Sheremetyevo Airport. The best travel conditions must be accepted prior to arrival at the Venzava border crossing with Belarus (rail, road or plane), the Turkish Straits (Marmara Sea or Bosphorus) and Ukrainian border crossings (plane).