how to add column in bottom in flutter code example

Example 1: flutter center row

mainAxisAlignment: MainAxisAlignment.center //Center Column contents vertically,

Example 2: align bottom flutter

// Use Align if have only one child, if have multiple:
return Column(
  crossAxisAlignment: CrossAxisAlignment.center,
  mainAxisSize: MainAxisSize.max,
  mainAxisAlignment: MainAxisAlignment.end,
  children: <Widget>[
      //your elements here
  ],
);