We can add taxonomies to content types as a field, like how we added fields earlier. To demonstrate adding the Category vocab as a field, navigate to /admin/structure/types/manage/post/fields or use the Admin toolbar to click on Manage - Structure - Content types and select the Manage fields button next to the Post content type.

We can now add our new Category Taxonomy vocab by performing the following steps:

1. Click on the Add field button.
2. Choose Taxonomy term from the Add a new field dropdown.
3. Label: Category.
4. Click on the Save and continue button.
5. Choose Unlimited from the Allowed number of values dropdown.
6. Click on the Save field settings button.
7. Choose Category from the AvailableVocabularies field under REFERENCE TYPE.
8. Click on the Save settings button.

We have now successfully added a Term reference field to our Post content type. We will visit adding a post in a moment. For now, we have one additional field that our content type would benefit from, and that is the ability for users to comment on each post.