When sending eBay messages with Orders, you can
Choose a message type (General, Multi-item shipping, Payment, Shipping),
type a subject and message,
use message template, and
add photo attachments.
Note: eBay's contact policy requires your messages to buyers are regarding a transaction between you and the buyer.
Message buyers Individually
In the Actions column, click the button that looks like a paper airplane:
Recommended: Apply a filter that shows only the buyers you need to message.
With the left column, select all orders, or multiple orders individually.
Then, click the Bulk Actions menu and select Send Messages