I recently ran into a slight dilemma. I downloaded some printable calendar months as Word docs, but they were each their own document by month. I wanted to put them all into one document and a simple copy-and-paste would normally have been fine. It did not work because they contained highly formatted tables and they just didn’t copy over correctly. Fortunately, Word can easily add files together.
First, click on the line you want the other Word doc to be pasted to. Then, go to Insert > File and select your other Word doc. That’s it. It will be inserted into the doc you’re in at the spot where you left the cursor.