Figma can approximate a squircle with its corner smoothing control, but for a pixel-exact superellipse — like a true iOS icon shape — the most reliable route is to import an exact squircle SVG. This page covers both, and when to use each.
Set the shape, download the SVG, and drag it into Figma — or copy the markup and paste it on the canvas.
Select a rectangle, set a corner radius, then open the corner smoothing control and raise it toward iOS (60%). This bends the corners toward a squircle and is great for quick UI work. The limitation: it is a smoothing approximation tied to a radius, not a parameterised superellipse, so it won't always match an exact n value or a specific reference shape.
Because the SVG is the precise mathematical outline, the corners are exactly right at any size — ideal for app icons and brand assets where the shape has to be perfect.
Figma has corner smoothing, which approximates a squircle. For an exact superellipse, import an SVG.
The "iOS" preset (~60%) gets close. For an exact match, import an SVG generated at n ≈ 5.
Place the squircle shape above the image, select both, and choose "Use as mask".