Yes. You can eat egg and apple together.
Because neither apple nor egg interfere with each other during digestion.
Furthermore, there is no scientific evidence that suggests not eating them together.
You can find many online forums where some people recommend not eating them together. But they didn’t provide any scientific evidence.
Traditional beliefs are not evidence.
The human body evolved on a diet of mixed foods. Enjoy them however you like. Apple and egg both are healthy foods.
Apple is good for your heart and diabetes; while egg is good for heart and eye.
If you experience any problem eating them together or one after another, talk to your healthcare provider. They will diagnose the reason and give proper advice.
Fact source: LiveStrong: