I see a ton of wedding cakes that look like the border is made of real ribbon.
Can you use real ribbon? If so is it food safe?

Thank you in advance

Yes, you can use real ribbon. It will absorb oil from the bc or fondant though and discolor (darken) from it. Some decorators line the ribbon with wax paper and some just pregrease the ribbon so it'll be darker but at least the same color all over and be even.