<ul>
    <li>HTML</li>
    <li>HTML</li>
    <li>HTML</li>
    <li>HTML</li>
    <li>HTML</li>
    <li>HTML</li>
    <li>HTML</li>
</ul>

 
ul{
  list-style: none;
  margin: 0;
  padding: 0;
}
ul li {
 position:relative;
 padding-left:25px;
 margin-bottom:15px
}
ul li:before {
 position:absolute;
 content:'';
 width:20px;
 height:20px;
 left:0;
 top:0;
 background:url(https://icons.iconarchive.com/icons/paomedia/small-n-flat/256/sign-check-icon.png) no-repeat center;
 background-size:20px 20px
}