Floating Tag

Step1: Setting up your work space.

Create a new image using the dimension  800 x 600. Set the background color to white. Create a new layer, Layer > New > Layer... (Shift+Ctrl+N).  Set the foreground color to #94e803

Step2: Creating the rectangle and the shadow.

Click on the Rounded Rectangular Tool and create the rectangle below.

Create a new layer, Layer > New > Layer... (Shift+Ctrl+N). Make sure this layer in under the button layer. Click on the Polygonal Lasso Tool using the setting below

Create the Lasso below

Click on the Paint Bucket and fill the selection with black, as shown below.

Click on the shadow layer and change the Opacity to 32% as shown below.

Finished:

That is it. Hope it came out to what you expected.