how to enter text in excel and have it automatcally appear in other cells

hello, i have an odd problem, I have to enter PO numbers (with letters) in some invoices more than once– long ones. it would be great if i could set up a formula so excel would copy whatever text i type in one cell and make it appear in other cells, he way it will mirror numbers via formulas. any suggestions? can’t find it anywhere. –fj