Q:

How to pre fill wordpress global option settings field ?

I have created an Option page for my wp theme with following code. It just shows a message textarea which user can fill. Now how to keep a default value in it say "Hello World" so user sees it first before filling and saving anything in the message text area.
add_action('admin_menu', 'add_gcf_interface');

function add_gcf_interface() {
    add_options_page('Global Custom Fields', 'Global Custom Fields', '8', 'functions', 'editglobalcustomfields');
}

function editglobalcustomfields() {
    ?>
    <div class='wrap'>
    <h2>Global Custom Fields</h2>
    <form method="post" action="options.php">
    <?php wp_nonce_field('update-options') ?>

    <p><strong>Message</strong><br />
    <textarea name="message" cols="100%" rows="7"><?php echo get_option('message'); ?></textarea></p>

    <p><input type="submit" name="Submit" value="Update Options" /></p>

    <input type="hidden" name="action" value="update" />
    <input type="hidden" name="page_options" value="message" />

    </form>
    </div>
    <?php
}

A:

Im not sure I fully understand your question, but if I have understood correctly, you are wanting to have a placeholder in your text area (i.e. default text that appears in the box prior to a user inserting their own text?).
If this is the case, then its quite simple, just add the placeholder attribute to your textarea tag as follows:
<textarea name="message" cols="100%" rows="7" placeholder="Hello World!">
   <?php echo get_option('message'); ?>
</textarea>

