Figuring this out took me longer than I expected it would. Attachments are not included as a column in a SharePoint list, but are saved in a folder that is named after the id of the item you attached the file to.
I ran into the problem of not being able to upload an indefinite number of attachments to a SharePoint list item. Using a file input could only upload file per input and I needed to allow the user to upload as many as they wanted. I ended up following this blog post.