Comments

Ctrl + Shift + F2
Added in Excel 2016
Comments are short bits of text that can be used to explain calculations, assumptions or to provide reminders.
A comment is a bit of descriptive text that enables you to document your cells and formulas.
You can only attach one comment per cell although you can make the comments as long as you want.
Adding comments to your worksheet cells has several uses:
1) Useful for tracking progress and for tracing your footsteps when handling complex formulas.
2) Useful for reminding yourself how certain areas of a worksheet work.
3) Useful for communicating with other people when you are sharing the same worksheet.

Displaying Comments

To display a comment, use the mouse to hover over the particular cell.
You can set the show/hide of individual comments by right clicking and selecting show/hide comment.

Adding Comments

Selecting Comments

Editing Comments

Removing Comments