1. First as always you need to open a new document 300 x 300 with white background. Now we need a new layer so choose Layer- New Layer. With your Rounded Rectangle Tool make a shape and after this another one in the Top Right Corner, held over the shape ,half outside. This will be the Label of our Content Box.
2. Now that we have the shape of the box we need to make it interesting. Go to Layer -Layer Style and choose Gradient Overlay. Here just set everything like me. The colors are (#6EC5FF) and (#A8E1FF).
3. Don't close the Blending Options and choose Stroke. After this you're done with the Styles.
4. Now get another Layer(Layer-New Layer) and with the Rectangular Marquee Tool choose the top of the box and fill it up with white. Set the Opacity to 75% and Soft Light . Now select the bottom and fill it with white.
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