У меня в коде используется ссылка для удаления записи из бд, как ее переделать в submit? Сделать такую же кнопку как "изменить" в коде показано.

Отрезок кода где нужно это сделать, весь код внизу

<?php
$isAddClient    = isset($_GET['add_client']);
$isDeleteClient = isset($_GET['delete']);
$isU            = isset($_GET['u']);
 
if($isDeleteClient)
{
    $id = $_GET['delete'];
    
    $stmt = $DBH->prepare("DELETE FROM `clients_table` WHERE `id` = :id");
    $stmt->bindParam(":id", $id);
    $stmt->execute();
    
    header("location: index.php?page=clients");
}
?>

<div class="wrap1" >
    <div class="table clients vopros">
        <div class="table-row">
            <div class="table-cell"> # </div>
            <div class="table-cell"> ФИО </div>
            <div class="table-cell"> Тел. номер </div>
            <div class="table-cell"> Номер машины </div>
            <div class="table-cell"> Паспортные данные </div>
            <div class="table-cell"> Действия </div>
        </div>
        <form class="table-row" onsubmit="return checkForm(this)" action="">
            <div class="table-cell"> <?= $row->id ?> </div>
            <div class="table-cell"> <input type="text" id="fio-1" name="fio-1" value="<?= $row->fio ?>" > </div>
            <div class="table-cell"> <input type="text" id="phone-1"maxlength="11" onkeyup="this.value = this.value.replace (/[^\d]/g, '')" name="phone-1" value="<?= $row->phone ?>" > </div>
            <div class="table-cell"> <input type="text" name="car-1" value="<?= $row->carNumber ?>" > </div>
            <div class="table-cell"> <input type="text" onkeyup="this.value = this.value.replace (/[^\d-]/g, '')" name="pass-1" value="<?= $row->passport ?>" > </div>
            <div class="table-cell"> <a class="silka" href="?page=clients&delete=<?= $row->id ?>"> Удалить </a> <input id="submit-form" type="submit" name="u" value="Изменить"></div>
            <input type="hidden" name="page" value="clients">
            <input type="hidden" name="id-1" value="<?= $row->id ?>">
        </form>
    </div>
</div>

Вот весь код

<?php require_once "head.php"; ?>
 
<?php
$isAddClient    = isset($_GET['add_client']);
$isDeleteClient = isset($_GET['delete']);
$isU            = isset($_GET['u']);
 
if($isDeleteClient)
{
    $id = $_GET['delete'];
    
    $stmt = $DBH->prepare("DELETE FROM `clients_table` WHERE `id` = :id");
    $stmt->bindParam(":id", $id);
    $stmt->execute();
    
    header("location: index.php?page=clients");
}
else if($isAddClient)
{
    $fio        = $_GET["client_fio"];
    $phone      = $_GET["client_phone"];
    $carNumber  = $_GET["client_carNumber"];
    $passport   = $_GET["client_passport"];
    
    $stmt = $DBH->prepare("INSERT INTO `clients_table` VALUES(NULL, :fio, :phone, :carNumber, :passport)");
    $stmt->bindParam(":fio", $fio);
    $stmt->bindParam(":phone", $phone);
    $stmt->bindParam(":carNumber", $carNumber);
    $stmt->bindParam(":passport", $passport);
    $stmt->execute();
    
    header("location: index.php?page=clients");
}
else if($isU)
{
    $stmt = $DBH->prepare("UPDATE `clients_table` SET `fio` = :fio, `phone` = :phone, `carNumber` = :car, `passport` = :pass WHERE `id` = :id");
    $stmt->bindParam(":fio", $_GET['fio-1']);
    $stmt->bindParam(":phone", $_GET['phone-1']);
    $stmt->bindParam(":car", $_GET['car-1']);
    $stmt->bindParam(":pass", $_GET['pass-1']);
    $stmt->bindParam(":id", $_GET['id-1']);
    $stmt->execute();
    
    header('location: index.php?page=clients');
}
if (isset($_POST['search_buttom'])) {
$carNumber = $_POST['search_car_number'];
$passport = $_POST['search_pass_number'];
$stmt = $DBH->prepare("SELECT * FROM `clients_table` WHERE `carNumber` = :carNumber OR `passport` = :passport");
    $stmt->bindParam(":carNumber", $carNumber);
    $stmt->bindParam(":passport", $passport);
    $stmt->execute();
    $row = $stmt->fetch(PDO::FETCH_OBJ);
}
 
 
?>   
<script type="text/javascript">
function checkForm(form){
    if (document.getElementById('fio-1').value=="") {
        document.getElementById('err_fio').innerHTML='ОШИБКА: Нет данных для изменения!';
        return false;
    };
    if (document.getElementById('phone-1').value=="") {
        document.getElementById('err_fio').innerHTML='ОШИБКА: Нет данных для изменения!';
        return false;
    };
    return true;
};
 
</script>
<div class="mass"> <p>ПОИСК</p></div>
<div class="wrap1" >
    <div class="table clients vopros">
        <div class="table-row">
            <div class="table-cell"> # </div>
            <div class="table-cell"> ФИО </div>
            <div class="table-cell"> Тел. номер </div>
            <div class="table-cell"> Номер машины </div>
            <div class="table-cell"> Паспортные данные </div>
            <div class="table-cell"> Действия </div>
        </div>
        <form class="table-row" onsubmit="return checkForm(this)" action="">
            <div class="table-cell"> <?= $row->id ?> </div>
            <div class="table-cell"> <input type="text" id="fio-1" name="fio-1" value="<?= $row->fio ?>" > </div>
            <div class="table-cell"> <input type="text" id="phone-1"maxlength="11" onkeyup="this.value = this.value.replace (/[^\d]/g, '')" name="phone-1" value="<?= $row->phone ?>" > </div>
            <div class="table-cell"> <input type="text" name="car-1" value="<?= $row->carNumber ?>" > </div>
            <div class="table-cell"> <input type="text" onkeyup="this.value = this.value.replace (/[^\d-]/g, '')" name="pass-1" value="<?= $row->passport ?>" > </div>
            <div class="table-cell"> <a class="silka" href="?page=clients&delete=<?= $row->id ?>"> Удалить </a> <input id="submit-form" type="submit" name="u" value="Изменить"></div>
            <input type="hidden" name="page" value="clients">
            <input type="hidden" name="id-1" value="<?= $row->id ?>">
        </form>
    </div>
</div>
<div class="keyy">
<form method='POST' action='' name='search_form'>
     <input type='text' name='search_car_number' value='' placeholder='Введите номер машины'> 
     <input type='submit' name='search_buttom' value='Поиск'>
</form>
</div>
<div class="mass"> <p>КЛИЕНТЫ </p></div>
<div class="wrap1">
    <div class="table clients vopros">
        <div class="table-row">
            <div class="table-cell"> # </div>
            <div class="table-cell"> ФИО </div>
            <div class="table-cell"> Тел. номер </div>
            <div class="table-cell"> Номер машины </div>
            <div class="table-cell"> Паспортные данные </div>
            <div class="table-cell"> Действия </div>
        </div>
        <form class="table-row" action="index.php?page=clients" method="get">
            <div class="table-cell">  </div>
            <div class="table-cell"> <input type="text" name="client_fio" placeholder="Петров Петр Петрович" required="on" autocomplete="off"> </div>
            <div class="table-cell"> <input type="text" maxlength="11" onkeyup="this.value = this.value.replace (/[^\d]/g, '')" name="client_phone" placeholder="88005553535" required="on" autocomplete="off"> </div>
            <div class="table-cell"> <input type="text" name="client_carNumber" placeholder="о000оо" required="on" autocomplete="off"> </div>
            <div class="table-cell"> <input type="text" onkeyup="this.value = this.value.replace (/[^\d-]/g, '')" name="client_passport" placeholder="111-123123" required="on" autocomplete="off"> </div>
            <div class="table-cell"> <input type="submit" name="add_client" value="Добавить клиента"> </div>
            <input type="hidden" name="page" value="clients">
        </form>
        <?php
        $stmt = $DBH->prepare("SELECT * FROM `clients_table` ORDER BY `id` DESC");
        $stmt->execute();
        
        while($row = $stmt->fetch(PDO::FETCH_OBJ)):
        ?>
        <form class="table-row">
            <div class="table-cell"> <?= $row->id ?> </div>
            <div class="table-cell"> <input type="text" name="fio-1" value="<?= $row->fio ?>" required> </div>
            <div class="table-cell"> <input type="text" maxlength="11" onkeyup="this.value = this.value.replace (/[^\d]/g, '')" name="phone-1" value="<?= $row->phone ?>" required> </div>
            <div class="table-cell"> <input type="text" name="car-1" value="<?= $row->carNumber ?>" required> </div>
            <div class="table-cell"> <input type="text" onkeyup="this.value = this.value.replace (/[^\d-]/g, '')" name="pass-1" value="<?= $row->passport ?>" required> </div>
            <div class="table-cell"> <a class="silka" href="?page=clients&delete=<?= $row->id ?>"> Удалить </a> <input type="submit" name="u" value="Изменить"></div>
            <input type="hidden" name="page" value="clients">
            <input type="hidden" name="id-1" value="<?= $row->id ?>">
        </form>
        <?php endwhile; ?>
    </div>
</div>