Can I send WhatsApp from a CRM Marketing campaign or an automation rule?
Yes: WASync is a Bitrix24 message provider, selectable in CRM Marketing, the "Send message" rule and the message button on a record.
Yes. WASync registers as a message provider in Bitrix24, so WASync WhatsApp appears wherever Bitrix24 lets you pick an SMS provider: CRM Marketing campaigns, the automation rule Send message, business processes and the message button on a lead, deal or contact. The text is sent as a free WhatsApp message from the number you set as default for this in the connection's settings, and the delivery status comes back to Bitrix24.
On a Business API number a free text reaches only customers who wrote to you in the last 24 hours; outside that window Meta refuses it and Bitrix24 shows the message as failed. On a QR number there is no such window. For messages outside the window use templates, from WASync Chat or from a Chat Flow.