var data = {
    "provider": "my_custom_platform",
    "email": "user@gmail.com",
    "action": "placed",
    "occurred_at": "2019-01-17T20:50:00Z",
    "order_id": "456445746",
    "order_public_id": "#5",
    "grand_total": 22.99,
    "total_discounts": 5.34,
    "total_taxes": 1.00,
    "total_fees": 2.00,
    "total_shipping": 5.00,
    "currency": "USD",
    "order_url": "https://mysuperstore.com/order/456445746"
};

$.ajax({
    type: 'POST',
    url: 'https://api.getdrip.com/v3/YOUR_ACCOUNT_ID/shopper_activity/order',
    data: data,
    headers: {
        'Authorization': 'Basic ' + btoa(apiKey)
    },
    dataType: 'json'
});