Letter Spacing

h2 {
  /* adds a 1px space horizontally between each letter;
     also known as tracking */
  letter-spacing: 1px;
}

The letter-spacing property is used to specify the space between the characters in a text.

! letter-spacing also supports negative values:

p {
  letter-spacing: -1px;
}

Resources: https://developer.mozilla.org/en-US/docs/Web/CSS/letter-spacing