Assuming that you have the url for the webpage in an attribute you can use the link button widget and use the attribute as the source for the button, see the documentation: https://docs.mendix.com/studio/page-editor-widgets-events-section#open-link-action.
Alternatively have a look at the JS URL Redirector widget from the marketplace: https://appstore.home.mendix.com/link/app/115219/Tammina-Solutions/Redirect-URL-Using-JS