I am new to wordpress. I am trying to call function myprefix_edit_user_cb() to get the edit form after user clicks on edit. 
function getdata()
{    
    $blogusers = get_users();
    foreach ( $blogusers as $user ) {
        echo '<span>' . esc_html( $user->user_email ) . '</span>';
        $editUrl = ??
        echo  "<a href='".$editUrl. "'>Edit User</a>"; 
        echo '<br>';
    }   
}
with function:
 function myprefix_edit_user_cb(){    
     $user = intval($_REQUEST['user']);
    echo '
                <form action="' . $_SERVER['REQUEST_URI'] . '" method="post">
                <label>Username</label>
                <input type="text" value="' .$user->user_login  . '"
                <input type="submit">
        ';
}
 
                        
According to me you need to put some request flag with your edit url.
Try the below code.
with action and callback function with flag :