Hi @dlewander, if you were adding media such as images/audio/video you could add them directly within the Kobo form as per these instructions: Adding Various Types of Media (image, audio, video) to a Form — KoboToolbox documentation
For other types of files - such as word documents - you will need to put the file somewhere else online (e.g. Sharepoint, Dropbox, Google Docs, whatever system you use) and then in the Kobo form you can put a hyperlink to the file.
Example in previous answer here: I would like to add a hyperlink to a question. Is it possible with KoBo? - #4 by Kal_Lam
All the best