Can u give me the complete sentence?

Hi Sinem, I think you are asking how to talk about an event that is happening for 2 days. Examples: The event is happening over the next two day. The event happens over a 2 day period. The event is 2 days long. The event lasts for 2 days. Those all mean the same thing. I hope it gives you a better idea of how it can be used.

I need context. It could be any of them.

All are correct .. it depends on the context.