The easiest way is to add the item to the next issue. Write a summary and include a link to where you can read more about the issue, for example a Phabricator task or an email in the open archives of a Wikimedia mailing list.
If you think something should be included but don't know how to add it, you can just add a new bullet point with the link and someone else will take a look at it. Like this:
You can also add the #user-notice tag to any Phabricator task.
If you for some reason want to do something else, maybe write a longer explanation, you can write on Talk:Tech/News, which the Tech News writers watch.
You can also contact the person writing the issue directly. This is not recommended if you want to be sure the item goes into the next issue unless you are very sure who to contact that particular week. It is usually handled by Johan, but he is occasionally travelling and might not be handling some issues. In that case either Trizek or Quiddity take care of it.