You can get information from Excel in a range of different ways. Here is one example
https://www.msofficeforums.com/word-...orm-entry.html
Choosing to open a file based on a filename is shown in this thread
https://www.msofficeforums.com/word-...cel-macro.html
Putting content into a header can be a bit more complex as we still don't know whether you want to add or replace content and how many headers are present in each document. If you get the rest of the code working, post the code you have come up with and we can finish it off.