Once your RFP is published, the Add New Section button along the lower left becomes Add Addendum.
Once the Add Addendum link is clicked, the following view will appear.
When you create this new Section, it'll be just like other Sections you have created in the past. You'll give a title, and assign a Default Writer and Default Approver for the the content. You can also choose a prior Section with the From Library option which will import for you.
Some organizations use an Addendum to publish answers to questions that have been received. You can build these in the body of the Addendum. And you don't have to ask any questions if you don't need any new responses. Sometimes we just add a yes/no question to get confirmation that proposers read and understand the information in the Addendum.
Once you approve this Addendum, your proposers are notified and they see this as a new Section at the end of their Proposal.
To approve and publish your addendum, just click the button Mark as Complete. If you are the approver as well as the writer, this will publish in one click. If you are the writer but not the approver, your approver will be notified. If you have the access/permission to approve, you can click on the Approve button which will then appear. So there are a couple options based on who you are and what you have access to do.