Part of the project cycle is to allow members of the project to review work in progress and provide comments and feedback. Confluence allows this to happen in a very fluid way as every page has the ability to record comments. 

To comment on a page:

• Scroll to the Comments section at the bottom of the page 
• Click in the box underneath the page content which has "Write a Comment" in it
• The box changes to a text editor so you can apply formatting, upload images etc :
  
• Once you have finished your comment click Save
• Your Comment now appears in the page and both the page author and anyone watching the page will be notified