
Change the Shape/Color of Cell Comments in Excel
1. Default shape for comments is rectangular — sometimes you may wish to use a different shape.
a. Add Change Shape Button to Quick Access Toolbar

ii. Choose More Commands > All Commands > Change Shape > Add >OK

iv. Right Click on comment and choose Edit.
v. Hover on border of comment until show appears and then click on Change Shape on Quick Access Toolbar.
vi. Choose shape needed
vii. Right click on comment cell and click show/unhide comment and position on page.