Which value of transform property is used to rotate the HTML element? code example

Example 1: image rotate with css

div {
  width: 80px;
  height: 80px;
  background-color: skyblue;
}

.rotated {
  transform: rotate(45deg); /* Equal to rotateZ(45deg) */
  background-color: pink;
}

Example 2: css transform property

Read this comprehensive article about CSS animation transform property. 
It also has many useful examples that help you in best way.

https://medium.com/swlh/learn-css-transform-animation-zero-to-hero-6a2a643bd56b