how to centralize an element in html code example

Example 1: center div horizontally and vertically

.parent {
  position: relative;
}
.child {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
}

Example 2: how to center align the html element in css examples

#inner {
  width: 50%;
  margin: 0 auto;
}

# center text
.center {
  text-align: center;
  
border: 3px solid green;
}