Each Project can have its own Wiki that can be found under the WIki tab.
How to Add a Project Wiki to Your Project
If your Project Does not have a “Wiki” tab then go to Project Settings > Advanced and enable the WIki
You will need to have a User Profile that is able to access the Project Settings tab such as a Project Manager.
Click Edit Project Settings on the Project Summary Page
Click the Advanced Settings button
Locate the “Enable WIki tab” radio button
Toggle to “Yes” position
You will now have a “Wiki” tab in your Project
You can now create your first Wiki Pages for your Project