Go to Email → Campaigns and click New campaign. Fill in:
- Name — for your own overview.
- Subject — what the recipient sees as subject.
- Message — the message body, with merge tags such as `{{client_name}}` for personalization.
- Recipients — pick from your clients, contacts, or a custom list.
- From account — which connected mail account sends the message.
- Schedule — immediately or at a chosen time.
After sending, you see per recipient whether the message was sent, opened, and/or clicked.