我希望所有客户在进入下一步交易之前输入表格中的特定号码

<form action='' method='POST'>
    <table align="center">

        <tr><td>Transaction Access Code:</td></tr>
        <tr><td><input type="password" name="code1"></td></tr>
        <tr><td class="button1"><input type="submit" name="submitBtn" value="Log In" class="button"></td></tr>
    </table>
</form>

     <?php
if(isset($_REQUEST['submitBtn'])){
include '_inc/dbconn.php';

$code1=$_REQUEST['code1'];

$sql="SELECT code1 FROM code WHERE code1='$code1'";
$result=mysql_query($sql) or die(mysql_error());
$rws=  mysql_fetch_array($result);


if($rws[0]==$code1 ){
header("customer_transfer_process.php");}        
   else
        header("customer_transfer_process1.php");}


?>

Your code had some errors. You also should always scrub user input when using it in a database transaction.

<form method='POST'>
    <table align="center">

        <tr><td>Transaction Access Code:</td></tr>
        <tr><td><input type="password" name="code1"></td></tr>
        <tr><td class="button1"><input type="submit" name="submitBtn" value="Log In" class="button"></td></tr>
    </table>
</form>

<?php

if(isset($_POST['code1'])){ 
    include '_inc/dbconn.php';

    $code1 = htmlspecialchars($_POST['code1']); // sanitize user input

    $sql="SELECT code1 FROM code WHERE code1='{$code1}'";

    $result = mysql_query($sql) or die(mysql_error());
    $rws = mysql_fetch_array($result);

    if($rws[0]==$code1 ){ //success, transfer
        header("customer_transfer_process.php");
    } else { //fail, send them somewhere else
        header("customer_transfer_process1.php");
    }
}
?>

   <?php
if(isset($_REQUEST['submitBtn'])){
include '_inc/dbconn.php';

$code1=$_REQUEST['code1'];

$sql="SELECT code1 FROM code WHERE code1='$code1'";
$result=mysql_query($sql) or die(mysql_error());
$rws=  mysql_fetch_array($result);



if($rws[0]==$code1 ){
 header('location:customer_transfer_process1.php');     }  
   else
        header('location:test.php');
        }

?>

First of all, don't use mysql_* functions anymore, they are removed in >= PHP7. Assuming you switch libraries (I will demonstrate using PDO), you should not append user-submitted data into the query, instead you should bind parameters/values. Last, you should probably employ a session to let your app know this user has already supplied the information required to start.

/_inc/dbconn.php

<?php
# Create connection. See documentation for more info on PDO
$con = new PDO("mysql:host=localhost;dbname=whatever",'root','');

/whatever_this_is_called.php

<?php
# NOTE: this php block should be placed at the top of the page, first thing
# Use session
session_start();
# Add this anyway
include('_inc/dbconn.php');
# Get action check
include(__DIR__.'/_inc/functions/getAction.php');
# Match form action
$action = getAction();
if($action == 'set_trans_code'){
    # Set default redirect
    $redirect = "customer_transfer_process1.php";
    # Prepare and execute
    $query = $con->prepare("SELECT code1 FROM code WHERE code1 = ?");
    $query->execute(array($_REQUEST['code1']));
    $result = $query->fetch(PDO::FETCH_ASSOC);
    # Check the key you called from db
    if($result['code1'] == $_REQUEST['code1']){
        # Assign code here, then check on the next page
        # Saves user from having to resubmit if user goes off page
        $_SESSION['transcode'] == $_REQUEST['code1'];
        # Overwrite default
        $redirect = "customer_transfer_process.php";
    }

    header($redirect);
    exit;
}
?>

<form action='' method='POST'>
    <!-- I like to set action names to differentiate tasks -->
    <input type="hidden" name="action" value="set_trans_code" />
    <table align="center">
        <tr><td>Transaction Access Code:</td></tr>
        <tr><td><input type="password" name="code1"></td></tr>
        <tr><td class="button1"><input type="submit" name="submitBtn" value="Log In" class="button"></td></tr>
    </table>
</form>

/_inc/functions/getAction.php

I would really only create something like this if you use a lot of form actions over and over.

<?php
function getAction($type='POST')
{
    $REQ = '_'.strtoupper($type);
    return (!empty(${$REQ}['action']))? ${$REQ}['action'] : false;
}