All foreigners (except citizens of some former Soviet republics) visiting Russia need a Russian visa to enter the country. In order to receive one, travelers need a Russian visa invitation from a Russian citizen or a company, which is then taken to a Russian embassy or Russian consulate, where the actual Russian visa is issued. Within three working days of arrival in Russia, the Russian visa needs to be registered by the person/organization that issued the invitation. If you do not register your visa in time, you may have trouble leaving the country.

There are many types of Russian visas, but most travelers get one of the below mentioned three kinds:

Tourist Visas
Russian tourist visas are best for short visits. To apply you must submit your original passport with at least 2 blank visa-designated pages (passport must be valid for at least 6 months after intended departure date from Russia).

Business Visas
In order to receive a Russian business visa you need an invitation from a Russian firm, which can usually be arranged through a visa agency.
Student Visas
Student visas are a great deal; they’re flexible, lengthy, and entitle you to Russian prices for trains, planes, the theater, and a host of other services. To receive one, you must prove enrollment at a Russian institution. If you are planning to enroll in a Russian university, the school authorities will help you arrange the visa.

Other Visas
Other types of visas include Transit Visas, On-the-Spot Visas, and Diplomatic Visas. Transit visas can be a cheap option for travelers headed for China or Central Asia, but it is often hard to make it in and out of the country in your allotted window of time. On-the-Spot Visas are dubious, not universally available, and very expensive. Diplomatic visas have a narrow range of applicability.