Does Viber approve company-initiated messages?

No. Once requesting a messaging service, you will have to provide a message sample and also label it as “transactional” or “promotional”. This gives Viber an overview of what your messaging needs are, though they don’t approve company-initiated messages (like WhatsApp Business, for instance).

ℹ️ Note that there's an exception for Russia, where Viber plays an active role in reviewing and approving those message templates in this country.