OpenCart Embed Code Instructions
Step 1. Edit file catalog/view/theme/{your-theme}/template/common/header.tpl
Step 2. Paste your Zotabox code at the bottom inside the {literal} <…> {/literal} tags. Eg.

{literal}<script async src=”//static.zotabox.com/5/f/5f6d7645b87e1238f90ad260dcbeb14f/widgets.js”></script>{/literal}

Step 3. Save your template file and refresh your website to activate the code.
 * You need to get your Zotabox embed code here: https://zotabox.com/dashboard/embeddedcode/
** You may need support from developer to update code