Metadata in your HTML5 content provides information that can help with such tasks as improving your in5-exported content's ranking in searches, intentionally hiding your content from searches, or redirecting users to a different URL
You can easily add metadata to all the pages your in5-exported content. Metadata is contained within <meta> tags, and <meta> tags go inside of <head> tags. With in5, you can attach an HTML resource containing a <head> tag and have the contents appear in the <head> tag of the output.
To add your metadata, create the HTML file that contains it. You can create the HTML file using a text editor such as TextEdit (macOS) or Notepad (Windows) or in an IDE such as Dreamweaver which is available to you if you have the full Adobe Creative Cloud subscription. For example, the following metadata that hides content from search engines could be saved as an HTML file to be used as an HTML resource:
<meta name="robots" content="noindex">
When you export from InDesign either by going to in5 > Export HTML5 with in5... or to in5 > Easy Export Wizard... and click the Advanced button, go to the Resources section of the Export HTML5 with in5 dialog, click the Browse... button to the right of the field below HTML to Append, and navigate to the HTML file that you created that contains the metadata.
For additional information about adding Resources when you export with in5, see Extending Functionality with External Resources.