The charts in your dashboard have a download button in the right upper corner. This allows you to export the data or embed that chart. This might be handy in some cases, but sometimes you don’t wish for those buttons to appear.
You can easily remove this download button from the 'interactivity' section of the chart options.

If you want the export disabled on all your charts, you can alternatively also opt to enforce this via CSS.
You can find this option in the overall dashboard settings underneath the ‘Advanced’ settings at the bottom. By activating the ‘Inject CSS Styles’, a pop-up screen appears where you can install the needed piece of code, which is the following.
.widget-export {
display: none;
}
Inject the CSS code by clicking on the blue button and the download buttons won’t appear in your dashboard anymore!