<span>23fdfdfd3<br>dfdsfdsfdsff</span>133

span {
  position: relative;
  padding-right: 5px;
  margin-right: 5px;
}
span::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  background-color: #000;
  border-radius: 5px;
  width: 2px;
  height: 100%;
}