There are two ways to add and update your shipping addresses.
1. The first is during the checkout process when you're placing an order:
Add your shipping address, then click the red "continue" button to proceed through the rest of the checkout process.
If you’ve already filled in your shipping details in the past and the checkout page transfers you straight to the last step of the process (Review order), you can change the settings and your preferred shipping address here by clicking the Change button under "Shipping Information."
2. The second way to manage your shipping addresses is in your account settings. To get there, login to your account and click on your profile image at the top right corner of the screen. When the menu appears, click "Settings." Then click "Shipping & Billing" from the menu at the top of the page. Here, you can add, update, and remove shipping and billing information from your account.