The address entered when registering an account on eBay can be modified after logging in and entering the account settings page. The specific steps are as follows:

1. Log in to your eBay account, point your mouse to the user icon in the upper right corner, and click the "Account Settings" menu.

2. On the "My Account" page, select the "Personal Profile" tab.

3. Click the "Address and Contact Information" option to see the entered address information.

4. Click the "Edit" button to make changes, and save the modified address information.

It should be noted that if you have already purchased an item on eBay and need to modify the delivery address, you need to modify it before submitting the payment, otherwise the order information may not match the actual delivery address, resulting in delivery problems.