Whether internal or not, leaving comments and uploading files works the same. To leave a comment, select the “Comment” or “Internal Comment” button, compose your message in the cell below, and press “Send” to attach your message.
To upload a file, select the “Files” or “Internal Files” button.
Then, select “New File” and upload directly from your computer or Google Drive.
Once uploaded, you can review any attached file by simply selecting it, and the file will automatically download onto your computer. To remove a file, select the trash can icon next to it and confirm the deletion.