CSS

change text in a div css

button {
  visibility: hidden;
}
button:after {
  content:'goodbye'; 
  visibility: visible;
  display: block;
  position: absolute;
  background-color: red;
  padding: 5px;
  top: 2px;
}

change text in a div css

.pvw-title span {
  display: none;
}
.pvw-title:after {
  content: 'whatever it is you want to add';
}

change text in a div css

<button>Hello</button>

button {
  background-color: green;
  color: black;
  padding: 5px;
}