how to add the property on mouse hover with bootstrap code example

Example 1: css hover

.a:hover{background-color: black;}

Example 2: on hover css

/* Changes an element's color on hover */

.selector {
	background-color: black;
}

.selector:hover {
	background-color: blue;
}

Example 3: how to show text at the time of hover in bootstrap

<div class="text-center my-3">
  <b-button v-b-tooltip.hover title="Tooltip directive content">
    Hover Me
  </b-button>

  <b-button id="tooltip-target-1">
    Hover Me
  </b-button>
  <b-tooltip target="tooltip-target-1" triggers="hover">
    I am tooltip <b>component</b> content!
  </b-tooltip>
</div>