Many content types can have attachments added. Such attachments then sit at the bottom of that page. An example is the Newsletter page.
The process is quite simple. Well below the Body box (where you type) there is a File Attachments section. Click on Browse to find the file on your computer, then click on Upload to import it to the website. Repeat if you have more than one. You can rename the files to something easier on the eye, and you can re-order how they show on the page by using the 'handles' on the left hand side of the table. Just click and drag. Then save.