editable grid add document link not working in site but works in object level

We need to see the implementation details.

Hi,
Can you please share some more details related to your issue?

1) What does your "Add Document" link/button actually call? (maybe you can share your code snippet here) 2) What permission does the site user have on that target folder?
3) What error (if any) do you see on the site? When you say it "doesn't work," does nothing happen at all, or is there a specific error message?

Please check the below screenshot related to Appian file upload component's target related permissions.

This sounds like a permissions issue. When you test the interface directly, it runs using your designer access, but the Site runs with the logged-in user’s permissions. Please verify that the Site users have access to the interface, document folder, and related objects. Also confirm that the document upload component is saving to a folder where those users have permission to upload files.