How to uninstall Extensions from organization?
Click on Integrations icon in top bar and select Extensions in the screen that appears. Here you can view the extensions in your organization. If you hover over an extension, you will get an option Uninstall on the right side. Click on it.
Note: This option will be visible only to the user who installed the extension from the Marketplace and to the admin. Therefore, only the user who installed the extension and the admin of the organization have permission to uninstall the extension.