Setting up Page Layouts
You must add the Validate Billing Address and Validate Shipping Address buttons to the Account object page layouts on your org Salesforce organization. See also organization..
On the Account page layout there are two sets of validate address buttons. When you hover over the buttons, the namespace of the buttons indicate that they belong to Accounting and Billing Central. Edit the page layout to add the buttons belonging to the application that your organization uses.
For information about editing page layouts, search for "Edit Page Layouts" in the Salesforce Help.