If you know the URL to your App catalog or are using a site collection app catalog, you can skip to step 5.

  1. Open the app launcher and click on Admin;

    Admin Center.png

  2. Open your SharePoint Admin Center;

    open-sharepoint-admin-center.png

  3. On the left panel, click on More features and select Apps;

    open-app-catalog.png

  4. Proceed by clicking on App Catalog;

  5. On the left pane, click on Apps for SharePoint;

    APPs for SharePoint.png

  6. Select the older package of the Web Part deployed, click at the option Files, in ribbon, and click to Delete Document;

    Delete files.gif

And that's it! The web part is now Uninstalled and Removed from your SharePoint site.