Edit in JSFiddle

<form action="" method="post" style="width:250px;margin:auto">
  <div class="get-inpust">
    <p>Имя</p>
    <div class="input-group">
      <input name="name" id="input-name"  required type="text">
      <div class="tooltip" id="tool-name"></div>
    </div>
    <p>Телефон</p>
    <div class="input-group">
      <input name="phone" id="input-phone" required type="tel">
      <div class="tooltip" id="tool-phone"></div>
    </div>
    <button type="submit">ОК</button>
  </div>
</form>
.input-group {position:relative}
.tooltip {position:absolute;right:0;top:-15px;}

.get-inpust p{
  text-align:left;
  margin: 10px 0 5px
}

.get-inpust{
  width:100%;
  padding: 10px;
  background: gray;
  border-radius: 20px;
}
.get-inpust input{
  width:100%;
  border: 2px solid green;
  padding:20px;
}
.get-inpust button{
  width:100%;
  margin-top:10px;
  padding: 20px;
 }
 
 *, :before, :after {
   box-sizing: border-box
 }