The Post Info module is in the Post modules category, which appears only when you're editing a Singular-type themer layout in Themer. It displays a single post or page's date, author, number of comments, and terms (categories, tags, or a custom taxonomy).
Each type of information can be displayed or hidden, and there are some additional settings for each type:
You can set the date format.
You can customize the text that is displayed for no comments, one comment, and more than one comment. The default text is "No comments," "1 comment," and "% comments," where % stands for the exact number of comments when there are more than one.
You can choose whether to display categories, tags, or a custom taxonomy, and you can choose the separator character when there's more than one. You can only display one of these types of terms at a time.
There are also the usual Advanced tab settings, which means you can customize margins, responsive layout, visibility, animation, and assign an ID or class name.