Hello,
are you using this in Excel online? Then you can't use macros or VBA. If you use Excel and Word for desktop, you can use VBA code, but it's not trivial to set up.
Basically, you need to create bookmarks in the Word document, then in the Excel code, open the Word document, jump to the bookmark and insert the value from the Excel cell. How exactly that code needs to be written depends a lot on your Excel and Word data structure.