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
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Click the Advanced Settings button
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Locate the “Enable WIki tab” radio button
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Toggle to “Yes” position
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You will now have a “Wiki” tab in your Project
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You can now create your first Wiki Pages for your Project