how to make font underline in css code example

Example 1: text-decoration css

h1 {
  text-decoration: overline;
}

h2 {
  text-decoration: line-through;
}

h3 {
  text-decoration: underline;
}

h4 {
  text-decoration: underline overline;
}

Example 2: how to underline font in css

h3 {
  text-decoration: underline;
}