Points to note:
- Ensure that the Illustrator document on your desktop that you want to share is a cloud document. If the document you want to share is stored on your computer, save it as a cloud document. Click Continue under Save as a cloud document to invite people option in the Invite to edit dialog.
- Ensure you're connected to the Internet to seamlessly work on shared cloud documents. If you're unable to find your shared cloud documents online or face any issues, see Why I can't see my cloud documents online?