“wpc_cf_after_form_field_edit” hook is used to add off to add the custom field in a section when editing form fields

Copy and paste the code below in the functions.php of your current theme.

function wpcargo_edit_display_client_accounts_custom( $flags ){
    ?>
        <tr>
            <th><?php esc_html_e('Do you want to display this on the Accounts Page?', 'wpcargo' ); ?></th>
            <td><input name="display_flags[]" value="account_page" type="checkbox" <?php echo is_array($flags) && in_array( 'account_page', $flags) ? 'checked' : ''; ?> /></td>
        </tr>
    <?php
}
add_action( 'wpc_cf_after_form_field_edit', 'wpcargo_edit_display_client_accounts_custom' );