Only with a custom theme. But custom themes are considered obsolete and will eventually go away. But why do this? Will your customers even know what this unusual, non-standard terminology means?
What is a stage? And a percentage requires a base to be applied to. Creativity in invoicing is almost always a bad idea.
Further, giving columns different names does not change their function.
Dear Tut, We are a design company and we have project which we invoice, the project will be divided into various stages and there will be % fee for each stage. so if we are allowed to change this title then we can write STAGE instead of Description, % Fee instead of Qty etc. Also we can’t add any percentage in the Qty column hence at the moment we write 0.1 for 10%. There is not change required for the functionality, only an option for changing the headings (look and feel)
Put the fee information in the description. Enter the amount, but no quantity. That should give you what you want in a form your customer can understand. Try it.