File Content vs. File from URL
There are two methods of uploading a file in Box: entering file content, and using a file's URL.
1. Upload file content-- Plain text file content can be uploaded using this action. Enter the text for your file in the File Content field. You will also need to select the folder you want to upload to in Box and enter a name for your file (including the extension you want to give it).
2. Upload file from URL-- This action can be used to upload a file directly from a URL rather than through entering text content. This allows you to upload non-text files such as images. In the Source URL field, enter the URL for the file you want to upload. Attachment URLs will typically end with the file extension for the file (in the example below, .jpg). You will also need to select the folder you want to upload to. Entering a file name is optional as the name of the file will be obtained from the URL by default.
Direct Linking to a File or Folder (Create file shared link/Create folder shared link)