Masking is a powerful technique in Illustrator that allows you to create complex shapes and effects. By using a mask, you can hide or reveal parts of an object, or create gradual transitions between colors and shapes.
One common use for masks is to create soft edges around an object. This can give your designs a more polished and professional look. To create a soft edge around a mask, you can use the Feather setting in the Mask Options dialog box.