What would be a good way to say we will accept product exchanges but not returns/refunds only store credit? (And are returns/refunds considered the same thing?)

I want to change my store from not accepting exchanges unless damaged or incorrect product to accepting product exchanges, but don’t know how to say it as I don’t want to offer refunds, just give a store credit if they don’t want the item. How would I go about saying this in a still convertible way? I don’t want it to be a turn off to my customers. And also I don’t know if returns mean the sam thing as refunds like I figure they are the same thing but idk. I’m just trying to figure out how to say it the most attractive way. Like for exchanges 14 days and for return with store credit 7 days. Would this be ok? I don’t want to do a whole 30 days. TIA!