The customer has the option to contact you under the product details view before placing the order.
You will see the questions sent by customers under the Support section:
Open the question and reply and expect more questions in the same trail. Make sure to follow up till you have closed the deal.
Once the order is placed you are getting an email notification. If the customer has not contacted you herself so far, then this would be the last time to do it by yourself. Make your customer happy and give some feedback. Confirm that you have received the order and that you are working to arrange delivery.
For any announcements open the Order Details on Vendor Dashboard >> Go to the “Add note” section on the right side of the page and type your message. By clicking the “Add Note” button the message will be uploaded to the order and also sent to the customer’s email address.