To exchange typically means to give something while getting something in return. For example, if you buy the wrong product at a store, you can go back to the store to exchange it. This means you're giving the wrong item back for the right item. If you exchange glances with someone, this means you both glanced at each other. I'm sure this is confusing, but hopefully it's still helpful.
'Interchange' means that one thing replaces another. It can mean the same thing as 'exchange,' but they're not always synonyms. In the United States at least, you'll usually hear the word 'interchangeable.' If two things are interchangeable, it means they can take each other's place.