无法将正确的数据输入MySQLi，它会一直显示0作为数据

Whenever i entered any data in the PHP page, it keeps adding 0 as the database. it says 0 in the mysql table i'm a new student and i really don't understand where the error is.

1. Here is my PHP and form coding.

   <form name="Submit" method="post" action="signupconn.php">
   <p>
     <input type="text" name="textfield" id="teachersname">
   </p>
   <p>
     <input type="text" name="textfield2" id="teachersphone">
   </p>
   <p>
     <textarea name="textarea" id="teachersadd"></textarea>
   </p>
   <p>
     <input type="text" name="textfield3" id="teachersic">
   </p>
   <p>
     <input type="text" name="textfield6" id="teachersqualify">
   </p>
   <p><input type="text" name="textfield7" id="classassigned"></p>
   <p>
     <input type="text" name="textfield4" id="teachersusername">
   </p>
   <p>
     <input type="text" name="textfield5" id="teacherspassword">
   </p>
   <p>&nbsp;</p>
   <p><input type="reset" value="Reset">
   <input type="submit" value="Sign Up"></p>
   </form>
   <?php
   $server="localhost"; //host Name
   $username="root"; //Mysql username
   $password=""; //Mysql password
    $dbname="taska_ceria_"; //Database name
   
    //Creating connection to mysqli.
    $conn=new mysqli($server,$username,$password,$dbname);
   
     //checking connection
   
     if($conn->connect_error){
     die("Connection failed" . $conn->connect_error);
     }
   
     if(isset($_POST['submit'])){
     $teachersname = 
     mysqli_real_escape_string($conn,$_POST['teachersname']);
     $teachersphone = 
     mysqli_real_escape_string($conn,$_POST['teachersphone']);$teachersadd 
     = mysqli_real_escape_string($conn,$_POST['teachersadd']);
     $teachersic = mysqli_real_escape_string($conn,$_POST['teachersic']);
     $teachersqualify = 
     mysqli_real_escape_string($conn,$_POST['teachersqualify']);
     $classassigned = 
     mysqli_real_escape_string($conn,$_POST['classassigned']);
     $teachersusername = 
     mysqli_real_escape_string($conn,$_POST['teachersusername']);
     $teacherspassword = 
     mysqli_real_escape_string($conn,$_POST['teacherspassword']);
   
      }
   
    $sql= "INSERT INTO 
    teachersinfo(teachersname,teachersic,teachersphone,teachersadd,
    teachersqualify,classassigned,teachersusername,teacherspassword)  VALUE 
    ('$teachersname','$teachersphone','$teachersadd','$teachersic',
    '$teachersqualify','$classassigned','$teachersusername',
    '$teacherspassword')";
   
     if($conn->query($sql) === TRUE){
      echo "Record Added Succesfully";
      header("location:body.php");
       }
      else
       {
     echo "Error" . $sql . "<br/>" . $conn->error;
      }
      $conn->close();
      ?>
   

   2. When I enteredthe data it says the data has been entered successfully but in the mysql table the content of the data has 0 on every attributes.

3.Please someone help me.

You have use id as input post,

<input type="text" name="textfield" id="teachersname">

use teachersname on name field.

<input type="text" name="teachersname" id="teachersname">

Then it may work properly