If your theme offers a widget area in top bar,simply use the Shortcode. Or you will need to edit your corresponding theme files (usually header.php) and insert following code at appropriate place in it
Embedding Currency Combo in top bar of AVADA theme
Following are the steps in which we will show you how to embed currency combo in top bar of the world’s most selling theme of all times, AVADA :
- Install Avada theme on your WP site.
- Go to Appearance and click on Editor.
- Open the file named as header.php. Most probably the title of the file will be “Theme Header”.
- Paste the following php code in this file at appropriate place.
- Click on Update File to save changes.
- Now view landing page of your WP site and you will get Currency Combo placed on the top bar of the page.
Read more here: do_shortcode WordPress function