To edit an attachment's properties, you need the 'Create Attachments' permission. See Space Permissions.

To edit the properties of an attachment:

1. View the page that contains the attachment.
2. 
3. Choose Properties next to the attachment. The 'Properties' screen wil appear.
4. Make your changes:
   
   • File Name — Rename or modify the name of the attachment.
   • New Comment — Update the existing comment or enter a new comment.
   • New Content Type — Change the content type of the attachment by entering a valid MIME type.
   • Page — Move the attachment to another page.
5. 保存を選択します 。