You might have observed on some sites showing an image, video, logo or anything with some embed code with a click to copy button. Mostly these types of Grab box are found in non-profit sites promoting any cause or campaign, it was widely used in SOPA-PIPA potests. You can use this type of widget in your WordPress site too by following few simple steps given here.
Install and activate Click to Copy Grab Box plugin ClickWP.Com. It allows you to easily generate code for your blog button. It adds a widget which you can access from Appearance -> Widgets page.
The widget displays a textarea showing your code for your readers to copy-paste in their blogs etc. The widget will even automatically generate the correct code for you, simply fill in fields in the widget and click Save.