Microsoft Excel offers a very good feature of adding comment to the cell that enables you to add any details about the cell, which is very helpful in the future, or for any other person in understanding the cell and its values.
Comment can be easily added to any cell by following the steps illustrated below:
This will open the box where you can type the comment. By default, it will contain the name of the user, which is logged in, and you can overwrite it as shown.
You can also change the comment in the future that was entered earlier, related to any cell by following the steps below. You can modify the comment you entered before as below.
Excel also lets you format the text that you added as comment for the cell. This includes various formatting options like changing the font, font size, color, etc of the comment. You can find this option by right clicking on the elected comment and selecting the option of Format Comment.