In the changelog you write a summery of what is changed in this version of the document.
The changelog for each version follows the version so you can go back in the versions and read.
The changelog can be mandatory for all new versions, this means that you have to write something in the changelog to be able to send it to verification. If the changelog is mandatory or not is set in the Variables and is valid for all documents.
Describe the changes and SEND for verification.
You can find the changelog for earlier verison of a document by selecting Document properties or Print folders
