You can upload files directly to your assistant's Files at:
To upload a file:
Click Upload.
Select the file you want to upload from your computer.
Click Open.
That's it! Your file will appear in Files and will be available for your assistant to use.
Once uploaded, you can ask your assistant to work with the file — for example, to review it, edit or modify it, extract information from it, create something new from it, or send it to someone.