Use the Excel comments feature when reviewing a worksheet so others know the feedback you have to share.
There may be times when you'd like to leave a reminder or note in a spreadsheet for yourself or someone else. Excel allows you to easily insert comments in a cell, as well as view and edit these comments.
Notice the small, red triangle in the upper-right corner of the selected cell. This triangle indicates that there is a comment associated with the cell.
To hide a comment after choosing to show it, simply right-click the cell and choose Hide Comment from the menu.