Hi travis k  - Posts Module is designed to be highly configurable - from full elaborate Blogs with attachments, to a simple tweet. As Will refers to above, you can edit the Posts form via Studio > Forms > Posts > Add Post.
You should also consider that UNA also has other options for content publishing, for a simple Tweet or Facebook style  post, you might want to use the Updates or Posts function in Timeline Module. You can access this form via Studio >Form > Timeline > Posts. We have that setup here on UNA.io - Updates for Short form posts, Posts for Blogs, Discussions for Forum.