<button>Оставить заявку</button>

body {
  background: black;
}

button {
  border: none;
  background: transparent;
  color: #fff;
  padding: 20px;
  text-transform: uppercase;
  font-family: Arial, sans-serif;
  position: relative;
}

button::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  height: 40%;
  top: 50%;
  border-left: 1px solid #fff;
  border-right: 1px solid #fff;
  transform: skewY(11deg) translateY(-50%);
}

button::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  width: 50%;
  left: 50%;
  border-top: 1px solid #fff;
  border-bottom: 1px solid #fff;
  transform: skewX(-50deg) translateX(-50%);
}