Black spots on the outside of apples is called Apple Scab. Bit hard to treat. Make sure that air can blow through the tree to help prevent the spores from landing on a fruit. Spray with a suitable fungicide, if you use sprays. Follow the instructions on the packing.
The apples are still edible, you just need to peel them and they will not store.
Black or brown marks inside the apple are more likely to be Bitter pit which is a calcium deficiency. Even harder to deal with.

thanks could you recommend a spray to use

Sorry, I don't spray fruit, so no experience to offer. Have used Copper sulphate in the past as it is reasonably organic, but I have a feeling you cannot buy it any more.
Have a look in a Garden Centre, they usually have shelves full of Sprays. Look for one specifically for Fruit.