how to change text css animations code example

Example 1: text change animation css

h1:before{
    content: 'Original Text';
    font-size: 600%;
    animation-name: head;
    animation-duration: 4s;
    animation-iteration-count: infinite;
}

@keyframes head {
    0% {font-size:600%; opacity:1;}
    25% {font-size:570%; opacity:0;}
    50% {font-size:600%; opacity:1;}
    65% {font-size:570%; opacity:0;}
    80% {font-size:600%; opacity:1; content: "Changed Text"}
    90% {font-size:570%; opacity:0;}
    100% {font-size:600%;opacity:1; content: "Original Text"}
}

Example 2: text animation css

.ml6 {
  position: relative;
  font-weight: 900;
  font-size: 3.3em;
}

.ml6 .text-wrapper {
  position: relative;
  display: inline-block;
  padding-top: 0.2em;
  padding-right: 0.05em;
  padding-bottom: 0.1em;
  overflow: hidden;
}

.ml6 .letter {
  display: inline-block;
  line-height: 1em;
}