There are various ways. The method you need to use depends on what part you need to center.
Source: https://css-tricks.com/centering-css-complete-guide/

Inline

Inline text or links within a block-level parent element.

.center {
  text-align: center;
}Code language: CSS (css)

Block level elements

.center {
  margin: 0 auto;
}Code language: CSS (css)

or

.center {
margin: auto !important;
width: 50% !important;
}Code language: CSS (css)

Multiple block level elements

For example, a form with fields such as Octorate.

.flex-center {
display: flex;
justify-content: center;
}Code language: CSS (css)