How to edit spacing between Flutter's TextFormField input and errorText

Add decoration in TextFormField Widget.

InputDecoration(
      contentPadding: EdgeInsets.only(left: 11, right: 3, top: 14, bottom: 14),
      errorStyle: TextStyle(fontSize: 9, height: 0.3),
)

There seems to be no way to do it unless you open the source code of InputDecoration (on your sdk folder flutter/packages/flutter/lib/src/material/input_decorator.dart)

look for _buildError
wrap the Text with Container like

Container(
    padding: EdgeInsets.only(bottom: 4),
    child: Text(
        widget.errorText,
        style: widget.errorStyle,
        textAlign: widget.textAlign,
        overflow: TextOverflow.ellipsis,
        maxLines: widget.errorMaxLines,
    )
)