How do I add an external tool to the New Rich Content Editor toolbar in an account?
As an admin, you can select up to two external tools to display in the toolbar of the New Rich Content Editor for all users in your account. Selected tool icons will display next to the External Tool icon.
Click the Admin link , then click the name of the account .
In Account Navigation, click the Settings link.
Click the Apps tab.
View App Configurations
Click the View App Configurations button.
Add Tool to RCE Toolbar
Find the external tool you want to add  and click its associated toggle . The toggle will only display for external tools that support placement in the New Rich Content Editor.
The New Rich Content Editor only supports up to two external tool icons in the toolbar. Once two tools have been selected, all other toggles will display as disabled .
View New Rich Content Editor
Selected tool icons will display next to the External Tool icon in the New Rich Content Editor toolbar for all users in your account.