Drop down Menus to use in WordPress Shortcodes plugin

I know there’ve been many posts about adding a drop down menu for archives and for categories but mine is a little different. I downloaded the WordPress Shortcodes plugin to my site and use it to display a welcome message, buttons, and contact information. I’d like to add a tab that will display a search button and drop down menus for my archives and templates.

I have tried using this code, but it will not work for me.

Browse by month:

<div id="archives"><select name="archive-dropdown" onchange="document.location.href=this.options[this.selectedIndex].value;">
  <option value=""><?php echo esc_attr( __( 'Select Month' ) ); ?></option>
  <?php wp_get_archives( array( 'type' => 'monthly', 'format' => 'option', 'show_post_count' => 1 ) ); ?>
</select></div>

Browse by category:
<div id="cats"><?php wp_dropdown_categories('show_option_none=Select category'); ?>

<script type="text/javascript"><!--
    var dropdown = document.getElementById("cat");
    function onCatChange() {
		if ( dropdown.options[dropdown.selectedIndex].value > 0 ) {
			location.href = "<?php echo get_option('home');
?>/?cat="+dropdown.options[dropdown.selectedIndex].value;
		}
    }
    dropdown.onchange = onCatChange;
--></script>
</div>

I’m very new to html, css, and php so please keep that in consideration when helping me out!

My website is https://www.craftywife.com.

Thank you in advance!