Android supports adaptive icons (foreground + background layer) and a separate round icon for launchers that display circular icons. Many developers provide a single full-bleed image and let the system or a tool generate the round mask.
Round icon in mipmap
Launcher icons are often shown as circles. You can supply ic_launcher_round.png in each mipmap folder (mdpi through xxxhdpi). These are the same pixel sizes as the main ic_launcher but masked to a circle. Generating both from one source image keeps branding consistent.
One image, all variants
Use a generator that outputs both the standard and round icon for every density. Then copy the mipmap folders into your app's res/ directory. No need to hand-draw round versions.