How do I change the name field in the Newsletter?

At the moment, we have a few contacts that don’t have their names next to their email addresses.

So when we send out our Newsletters, it says “Hi Friend” - How do we change it to just say Hi instead of " Hi Friend"

You need to change the merge default for whatever field you are merging in …looks like first name in your example. Check out this article and here is a screenshot to show you what to look for