How do I edit this comment or shout out box?

Hello, I have an Excel sheet I created based off an inventory template. 

I have my sheet running as required for work, however there are text boxes with discerptions on the headers. 

I have tried searching for ways to remove and or edit with no luck. Can anyone help or point me in the right direction?

Thank you in advance. 

Screen s hot of A1

Screen shot of Header E2