The WhatsApp 24-hour window
Why you sometimes need a template to reply on WhatsApp.
In Salescom: Conversations > (a WhatsApp chat)
WhatsApp only allows free replies within 24 hours of the customer's last message. This is WhatsApp's rule, not Salescom's.
After 24 hours, the reply box asks you to send an approved WhatsApp template instead. Once the customer replies, the 24 hours start again.
Templates are created and approved through Meta, and listed in Settings > WhatsApp templates. See WhatsApp templates.