<form action="#">
  <input type="search" placeholder="Phone Number" >
  <button type="submit">Send Link</button>
</form>

*{
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

form{
  display: inline-block;
  vertical-align: top;
  position: relative;
}
input[type="search"]{
  outline: none;
  border: 1px solid #222;
  padding: 5px 50px 5px 30px;
  display: block;
  font-size: 16px;
  font-weight: 700;
  width: 100%;
  height: 50px;
  background: #7e17da87;
  border-radius: 25px;
}
input::placeholder{
  color: #fff;
}
button[type="submit"]{
  position: absolute; 
  top: 1px; 
  right: 1px;
  bottom: 1px;
  z-index: 9;
  outline: none;
  border: none;
  display: inline-block;
  background: #fff;
  font-size: 16px;
  font-weight: 700;
  color: #a207ff;
  padding: 10px 25px;
  border-radius: 25px;
  cursor: pointer;
}
button[type="submit"]:hover{
  background: #a207ff;
  color: #fff;
}