To access the WhatsApp Businesses Nearby feature, users shall open the WhatsApp Business app and then head over to the search section. Read details here.
Once this feature is rolled out for WhatsApp Business account users, they will see Contacts, Non-contacts and Unread categories while searching on the app.
At present, WhatsApp uses two ticks to inform the sender that a message has been delivered to the intended receiver. These ticks turn Blue once the receiver has read a particular message.