Russian tourist invitation is required for most nationals to be able to apply for a visa to travel to Russia on tourism. The document is a PDF file in A4 format. It contains information such as your name, nationality, date of travel, purpose of travel, cities to visit in Russia, hotel or Airbnb and host organization details. You will have to submit a copy of the Russian tourist invitation (aslo called Russian tourist voucher) at the consulate. Some of the information on the document will be used to fill the online visa application form. 
The Russian tourist invitation letter could be for single entry or double entry into Russia.

Ukraine has an awesome visa agreement with many countries. Citizens of the following countries need a visa to enter Ukraine:
Afghanistan, Algeria, Angola, Australia, Bahamas, Bahrain, Bangladesh, Barbados, Belize, Benin, Bhutan, Bolivia, Botswana, Burkina Faso, Burundi, Cambodia, Cameroon, Cape Verde, Central African Republic, Chad, China (PRC), Hong Kong, Colombia, Congo (the Democratic Republic, Congo (the People’s Republic), Costa Rica, Côte d’Ivoire, Cuba, Djibouti, Dominican Republic, Democratic People’s Republic of Korea, Ecuador, Egypt, El Salvador, Equatorial, Fiji, Guinea, Eritrea, Ethiopia, Gabon, Gambia, Georgia, Ghana, Grenada, Guatemala, Guinea, Guinea-Bissau, Guyana, Haiti, Honduras, India, Indonesia, Iran,Iraq, Jamaica, Jordan, Kenya, Kuwait, Laos, Lebanon, Liberia, Libya, Madagascar, Malaysia, Maldives, Mali, Mauritania, Mauritius, Mexico, Mongolia, Morocco, Myanmar, Namibia, Nepal, New Zealand, Nicaragua, Nigeria, Oman, Pakistan, Palestine, Peru, Philippines, Puerto Rico, Qatar, Rwanda, Saint Lucia, Saint Vincent and the Grenadines, Samao, San Tome and Principe, Saudi Arabia, Senegal, Serbia, Seychelles, Sierra Leone, Singapore, South Africa, Sri Lanka, Sudan, Syria, Tanzania, Thailand, Timor Leste, Trinidad and Tobago, Tunisia, Turkmenistan, Tuvalu, Uganda, Vanuatu, Venezuela, Vietnam, Yemen, Zambia and Zimbabwe.
More details here.

1. 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).
2. Two copies of Russian visa application form, completed and signed. Fill it here. 
3. Two passport-size photos signed on the back.
4. A Russian tourist invitation letter (Russian tourist voucher) or a russian business invitation letter from an authorized travel company which shows the reference number and confirmation number for the visa.
5. Confirmation of hotel arrangements from an authorized Russian travel company, or directly from the Russian hotel, showing reference number and confirmation number for the visa.
The document we will send you is number 4

For most countries that require a Russian tourist invitation letter, the consulars now accept an electronic copy of the invitation. For high migration risk countries like Syria, Afghanistan and Iraq, we advise that you confirm from the Russian consular in your country of visa application before you apply for a Russsian tourist invitation letter on our website.

The confirmation or voucher number is the unique number of your invitation. It is on the right part of the tourist voucher.

The reference number is the number by which the tour operator is registered. It is the number after “PTO”.

Aim tourism is a trip of 7 days or less. The purpose of the short visit may be for a business-related purpose, for the purpose of participating in exhibitions or to seek medical examination or medical advice. You will also need a Russian tourist invitation for an aim tourist visa. The Russian tourist invitation, however, must have aim tourism written on it. Apply and get your aim tourist invitation here.

The Russian business visa is for a stay in Russia for 90 days maximum for every period of 180 days. This rule might be different for migration safe countries. You will also need a business invitation letter in order to apply for this visa. Get your Russian business invitation letter here

Please ensure you review your data before submitting the form. If there is a mistake on your form, we will make a one-time free correction for migration-safe countries, and subsequent changes may attract additional charges. Corrections for migration-risk countries may attract additional charges.

For migration-safe countries, we send the Russian tourist invitation to your email within 5 hours of payment. For migration-risk countries, we send the Russian tourist invitation to your email within 24 hours of payment. If after the specified hours, you did not receive the invitation in your email, please chat with us or send us an email: [email protected]

We send the Russian business invitation to your email within the specified day on your applicatio. If on the specified day you did not receive the invitation in your email, please chat with us or send us an email: [email protected]

For those whose stay in Russia is less than 7 days, it is not required to register their visa.
For those whose stay in Russia is more than 7 days, it is required to register their visa within 1-2 days of their arrival. Contact your hotel regarding registering your visa.