<div class="container">
  <button class="btn btn1">Hover Me</button>
  <button class="btn btn2">Hover Me</button>
  <button class="btn btn3">Hover Me</button>
  <button class="btn btn4">Hover Me</button>
</div>

body{
  margin: 0;
  padding: 0;
  background: #f1f1f1;
}
.container{
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%,-50%);
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
}

.btn{
  width: 220px;
  height: 50px;
  background: #6a89cc;
  margin: 40px;
  border: none;
  outline: none;
  cursor: pointer;
  color: #fff;
  font-family: "montserrat",sans-serif;
  text-transform: uppercase;
  font-size: 16px;
  transition: 0.4s;
  transform-style: preserve-3d;
  perspective: 800px;
}

.btn::after{
  content: '';
  position: absolute;
  background: #4a69bd;
  transition: 0.4s;
}

.btn1:hover{
  transform: rotateX(-20deg);
}
.btn1:after{
  width: 100%;
  height: 24px;
  top: -24px;
  left: 0;
  transform-origin: 0 100%;
  transform: rotateX(90deg);
}

.btn2:hover{
  transform: rotateX(20deg);
}
.btn2:after{
  width: 100%;
  height: 24px;
  top: 100%;
  left: 0;
  transform-origin: 0 0;
  transform: rotateX(-90deg);
}

.btn3:hover{
  transform: rotateY(20deg);
}

.btn3::after{
  width: 30px;
  height: 100%;
  left: -30px;
  top: 0;
  transform-origin: 100% 0;
  transform: rotateY(-90deg);
}

.btn4:hover{
  transform: rotateY(-20deg);
}

.btn4::after{
  width: 30px;
  height: 100%;
  left: 100%;
  top: 0;
  transform-origin: 0 0;
  transform: rotateY(90deg);
}

/*
* https://www.darkcode.info/2018/12/buttons-with-3d-effect-on-hover-using.html
*/