Step 7: Select A Round, Soft-Edge Brush
Right-click (Win) / Control-click (Mac) anywhere inside the image to open the Brush Preset picker and choose a round, soft-edge brush from the list. I’ll choose the very first one in the top left corner by clicking on its icon. This gives us a brush with a Hardness value of 0%, or in other words, the softest edge possible. Press Enter (Win) /Return (Mac) when you’re done to close out of the dialog box: