It looks like you have apple scab. We are seeing it a lot this year, probably as a result of all the rain. 

Below is some good information on it. Be sure to do excellent clean up as leaves and apples fall. The fungus overwinters in the debris. Bag it and send it with your city compost. You can prune out dead branches. 

It is mostly cosmetic if your tree doesn’t suffer year after year. 

https://extension.umn.edu/plant-diseases/apple-scab