<form>
    <input type="text">
    <input type="text">
    <input type="text">
    <button>Отправить заявку</button>
</form>

form {
    position: relative;

    margin-top: 50px;
    padding: 50px 0 30px;

    text-align: center;
    
    border: 1px solid #ccc;
}

form::before {
    content: "";
    position: absolute;
    top: 0;
    left: 50%;
    transform: translate(-50%, -50%);

    width: 70px;
    height: 70px;
    

    border: 10px solid #fff;
    border-radius: 50%;
    background: #eee;
}

button {
    position: absolute;
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translate(-50%, 50%);
  
  border-radius: 20px;
  border: 10px solid #fff;
  padding: 5px;
  cursor: pointer;
}