how tu put an element in the center of the body code example

Example 1: align in the middle of page html

.centered {
  position: fixed;
  top: 50%;
  left: 50%;
  /* bring your own prefixes */
  transform: translate(-50%, -50%);
}

Example 2: html center body

body {
max-width: max-content;
margin: auto;
}