It looks like your tree has apple tree maggots. Small flies lay eggs in the apples. When the eggs hatch the maggots tunnel into the fruit until mature. There are chemical free ways to control in future years. Once the tree fruits out you can bag or stocking each apple to protect it. Below is a link to an article that explains the maggot life cycle and ways to treat. https://www.extension.umn.edu/garden/yard-garden/fruit/apple-pest-management/maggot/