Identical is only an adjective. Identical can describe another object, like "identical twin brothers", "identical cars", etc. Identical is two or more objects/subjects that are 100% like each other in appearance. Same can be a noun or an adjective. "your jacket and my jacket are the same", or "We have the same jacket". Same means it is almost completely identical, but you don't know if they differ in slightly different ways. "We have the same jacket, but different sizes". Same might also apply to thinking "we have the same idea". There are no clear rules in English for the use of these two words. Identical is used when you want to be precise/scientific/detailed, while Same is used informally in conversation, or general writing.