Custom delete option button in plugin settings

I managed to add delete button this way, it also may be used to add any extra submit button.

Create a submit button with name and array attribute:

function mw_options_wc_order_attachement_1()
{
    ?>
        <input type="file" name="mw_options_wc_order_attachement_1" id="mw_options_wc_order_attachement_1" value="<?php echo get_option('mw_options_wc_order_attachement_1'); ?>" />
        <?php echo get_option("mw_options_wc_order_attachement_1"); ?>
        <input type="submit" name="submit[delete_attachment_1]" class="button button-primary" value="Delete" />
    <?php
}

Register setting with callback function, mw_options_wc_order_attachement_1_handle is the name of the function in my case.

register_setting("mw_options", "mw_options_wc_order_attachement_1", "mw_options_wc_order_attachement_1_handle");

Make the callback function something like this:

function mw_options_wc_order_attachement_1_handle($options)
{

    if (isset($_POST["submit"]))
    {
        $submit_button = $_POST["submit"];

        if (isset($submit_button["delete_attachment_1"])) 
        {
            // delete file
            wp_delete_file('YOUR-FILE-SERVER-PATH');
            return ''; // returns empty option value to settings
        }
    }

 }