If you are interested in having Amazon fulfill your orders, see Use Fulfillment by Amazon to Ship Your Handmade Products.
The process of fulfilling an order gives great overview on this process. Follow
these three guidelines to avoid customer order cancellations and late shipment penalties:
These guidelines will ensure that customers receive their orders within the time communicated on the product page.
When listing your handmade products, you must enter a quantity and production time for each product on the Required Info section of the Add a Product tool. The quantity you enter should represent the number of units you can create within the production time you specify.
If you enter zero, your product page will read "out of stock." The production time you enter should equal the number of days from when you receive an order for that product to when you can ship it. This can be from 1 to 30 days and should include the time to produce any customizations you might offer. You can set the production time for a product when you create a listing or you can go back at any time and edit the production time for an existing product.
If at any time you are unable to create or ship a product, be sure to change the quantity available to zero to avoid taking more orders and increasing your risk for customer cancellations. You can do this by finding the product you would like to update on the Manage Inventory page, in the Edit drop-down menu for the product in question, select Edit. This will take you to the listing for your product, where you can change any information you would like.
Once a customer places an order, you must confirm shipment within 30 days of the order date. If you fail to do so, Amazon will cancel the order and you will not receive payment, even if you shipped the order. You can review and confirm customer orders in the Manage Orders tool on the Orders tab of your Seller Central Account.
For every order that you receive through Amazon, you will see a “Ship by” date, which is the production time you set for the product.
Be sure to confirm shipments in the Manage Orders tool only when the product has been shipped to the customer and within the production time you set for that product, before or on the “Ship by” date: