This will depend on who you use as your official sponsor. If you apply independently, you will need to contact each hotel to get a Letter of Invitation for your length of stay in that particular hotel. In the event you are staying in several hotels, the easiest and often best way to handle this, is to apply through an authorised Russian tour operator where this can all be arranged in one place.
Please be aware that although you are not obliged to stay in the hotels you list on your invitation letter, the hotels may charge you on the debit/credit card you used to make the reservation (especially if they included the invitation free of charge) in case of a no-show.
We have offices in Moscow and Volsky and can act as your official sponsor when applying for a Russian visa Letter of Invitation.