UV Unwrap and Relax

This feature performs several tasks at once, all of which can be activated either simultaneously or selectively. Its primary function is to generate an automatic UV unwrap that takes into account existing Seams and defined Pins. The surfaces can be automatically unwrapped in terms of their shape and size to minimize distortions compared to the original polygons. With sensibly placed Seams, this is often the only tool you need to generate a high-quality UV unwrap.

Before running the tool, you can select the edges and save them as Seams along which the UV mesh should be split. This allows you to unwrap even complex shapes and, for example, divide them into separate UV islands. You can also limit the unwrapping to a specific selection by selecting polygons.
You can access the tool's settings by clicking the gear icon.