Tags allows for extreme flexibility in tracking, organizing, and following issues or audits. Tags are a custom text or a label that can be applied to an issue or audit. This is no limit to the number of tags that can be added. These tags may be used to highlight issues, such as a regulation that relates to and item. With tags set, you can the filter the items displayed on the dashboard, audit tab, issues tab, or generate reports based on these tags.
Here is the link to the article "How do I Add or Edit a Tag."