Instruction to apply multiple licenses

The webpages provide instructions about applying a license:

> Create a text file (typically named LICENSE or LICENSE.txt) in the root of your source code and copy the text of the license into the file.

That would not work if a repository requires multiple licenses. (e.g. GPL-3.0 for source code and CC-BY-4.0 for docs)

As I said the problem is that one repository might have a lot of (modules|packages|…) and it is not clear how a user (me) can apply multiple license to a repository.

1. Should a user create a file named as a license and put that license’s contents into the file per each license?
2. Should a user create one big LICENSE file and put every licenses’ contents into the file?
3. Other ways?

What do you think?

Thanks!