Use Any Shape As A Selection

If you want to use a shape, such as the Heart or Star, as a selection, then press the Q key to enter the Quick Mask Mode. Then you can use any of the shapes to make and adjust selections. Remember to set the Shape tool to “Pixels” in the Options Panel.

Use black to hide pixels and white to reveal them. You will see a red overlay over sections of the image that will be hidden. Exit the Quick Mask Mode by pressing the Q key once again.