If you would like to create a newsletter but are not strong at design, what feature in the publisher application provides a sample design? templates guides page parts placeholder

I'd say templates

When Publisher is launched, you will see a number of templates to choose from. To create a publication or a newsletter, you can select a template you would want to use and that fits what you want your newsletter to be.

The feature in the Publisher application that provides a sample design is Templates.
Microsoft publisher turns the computer into a desktop publishing center; allowing users to create a number of professional looking documents. A template is a form, pattern or mold used as a guide to making a document or something. For example a document in which the standard opening and closing parts are already filled in is a template that one can copy and then fill in the variable parts.