How do I create a legend or key for an Excel worksheet?

[ditzylittlepixie]

I want to put a key for an excel worksheet, but I can only find advice on how
to create a legend for a chart. Is there a way I can do this?

 

[Dave Eade]

What do you want a "key" to?

I usually use a "text box" to put info on a spreadsheet that doesn't
natrually sit in a cell.