Recently, I have received the following comment.
When submitting your revised manuscript, you will be able to respond to the comments made by the reviewer(s) in the space provided. You can use this space to document any changes you make to the original manuscript.
Furthermore, I have received the original manuscript (in .pdf) as an attachment. The attached manuscript is highlighted with some red color underlined pop-ups messages.
I am having a doubt regarding the space. What is the space the editor is talking about? Is it the space specified in the original manuscript, or do I need to incorporate the same using a new response sheet.