JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="fa" dir="rtl">
<head>
    <meta charset="UTF-8">
    <script src="script.js"></script>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>سامانه دریافت رمز اینترنت</title>
    <style>
        .display-form{
            margin: 75px auto;
            width: 500px;
            height: 500px;
            box-shadow: 0 10px 30px rgba(28, 76, 156, .15);
        }
        .displayOrg{
            padding-top: 20%;
        }
        input{
            text-align: center;
            margin: 0px auto;
            display: block;
            width: 200px;
            height: 35px;
            border: none;
            background-color: #F2F2F2;
            border: 5px;
            font-size: .85rem;
        }
        button{
            text-align: center;
            margin: 0px auto;
            display: block;
            width: 200px;
            height: 45px;
            background-color: #2979ff;
            border:1px solid #0b6ab6;
            color: #fff;
            border-radius: 3px;
            font-size: .99rem;
            cursor: pointer;
        }
        button:hover{
            background-color: #005cf5;
            -webkit-transition: all ease-in-out .4s;
        }
        .inputClick{
            display: none;
        }
        #form{
            display: block;
        }
    </style>
</head>
<body>
    <div class="display">
        <div class="display-form">
            <div class="displayOrg">
                <form id="form">
                    <input type="text" placeholder="شماره دانشجویی" class="input1">
                    <br>
                    <input type="text" placeholder="شماره شناسنامه یا ملی" class="input2">
                    <br>
                    <button class="buttonForm" onclick="recive()">دریافت</button>
                    <input type="text" class="inputClick">
                </form>
            </div>
 ...

JavaScript

let input1=document.getElementsByClassName('input1').value;
    let input2=document.getElementsByClassName('input2').value;
    let recive=function(){
    let totalValue=input1+input2;
    return totalValue
}