Do holders of an ordinary passport issued by Vanuatu need an invitation for a regular Russian visa?
Short answer
Current official Russian sources conflict on Vanuatu purpose restrictions: the Russian Embassy in the UAE says the up-to-90-day visa-free route excludes work, study and commercial business, while the current KD MID entry table says all passport types are visa-free for up to 90 days without that carve-out. Confirm the applicable route with the competent Russian mission before relying on an invitation or visa category.
Verified answer
Because the permitted official sources do not agree, this answer does not state categorically that work, study or commercial business always requires a regular visa for an ordinary passport issued by Vanuatu. If the competent Russian mission confirms that a regular visa is required, the supporting document then depends on the category: tourist acceptance confirmation for tourism; the prescribed invitation or decision for business, humanitarian, private, study or work travel; and onward-travel documents rather than an invitation for transit.
The linked Vanuatu entry Rule Version preserves the UAE Embassy's explicit purpose exclusions. The linked 90-day context Rule and its current KD MID evidence publish visa-free entry for all passport types for up to 90 days without those exclusions. This reviewed Answer Version exposes the unresolved official-source conflict instead of silently selecting one source.
What to do next
Open both linked official sources and ask the Russian consular institution responsible for the traveller's place of permanent residence to confirm the route for the planned purpose. Only if a regular visa is required should the applicant select a visa category and follow that mission's current supporting-document checklist.