Search results query text fields and tag fields

My expectation with searching was that in addition to fields marked for inclusion in search, I would be able to have a tags field, add tags, and those tags would be included in the search to display entries. Using the example search code from the documentation, when searching for a specific tag, it does not pull the entry that has that tag. What do I need to do in order to have those entries that have the tags shown in the search results?