Adjusting text spacing

In CSS, you specify the amount of white space
between each letter or word by giving a length value
for the letter-spacing and word-spacing properties, respectively.
The amount of space can be in px, pt, cm, em, etc.

In Flutter, you specify white space as logical pixels
(negative values are allowed)
for the letterSpacing and wordSpacing properties
of a TextStyle child of a Text widget.

letter-spacing: 4px;
}

letterSpacing: 4, 
        ),
      ),
    ),
  ),
);

Making inline formatting changes

A Text widget lets you display text
with some formatting characteristics.
To display text that uses multiple styles
(in this example, a single word with emphasis),
use a RichText widget instead.
Its text property can specify one or more
TextSpan objects that can be individually styled.