Number of users a Business can Message after going Live on WhatsApp Business API Depends on Facebook Business Manager Verification

If Facebook Business Manager is Verified, business can Send messages to more than 250 Users/24 hours
Tier 1 : 1000 Users/24hrs, Tier 2 10,000/24hrs Tier 3 100,000/24hrs Tier 4 : Unlimited)

If Facebook Business Manager is NOT verified, Business can Send Messages upto 50 users/24 hours 33