Answers for "How to create a circle icon button border radius in Flutter?"

Round button with text and icon in flutter

OutlinedButton.icon(
              icon: Icon(Icons.home),
              onPressed: (){}, 
              label: Text('OutlinedButton'),
              style: OutlinedButton.styleFrom(
                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20.0))
              )
            ),

flutter icon button circle

ClipOval(
  child: Material(
    color: Colors.blue, // button color
    child: InkWell(
      splashColor: Colors.red, // inkwell color
      child: SizedBox(width: 56, height: 56, child: Icon(Icons.menu)),
      onTap: () {},
    ),
  ),
)

round border button flutter

RawMaterialButton(
  onPressed: () {},
  elevation: 2.0,
  fillColor: Colors.white,
  child: Icon(
    Icons.pause,
    size: 35.0,
  ),
  padding: EdgeInsets.all(15.0),
  shape: CircleBorder(),
)