Hi there and welcome
What you will need to do is enable track changes on the document so that you can edit it and it records this.
In order to do this, On the Review tab, under Tracking, click the Track Changes switch to turn on track changes.
Then when you make changes, they will be highlighted so the reviewer can then see these and accept or reject them.
You can see and overview of this functionality here
If you would like any additional information or assistance, please do not hesitate to let me know.
Else if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.