Umm.... yeah. It's called Word. There are a variety of approaches one could
use, depending on whether the original formatting needs to be retained.
Assuming it does, one approach:
1. Open the original file. Choose File - Save As and give it the name of the
first file you want to create. Delete everything you don't want in that
file, then save/close it.
2. Open the original file. Choose File - Save As, and give it the name of
the second file you want to create. Delete everything you don't want in that
file, then save/close it.
Etc.
Or... if you've set it up using Heading # styles, you might find that the
Master Document approach would give you what you want (assuming Master
Document works for you... it doesn't always work for everyone, especially in
earlier versions of Word).