If you give an apology, you say you are sorry for doing something wrong.
If you give an excuse, you provide a reason or explanation for the problem (this can
be seen as trying to avoid responsibility).
▶️ Apology: “I’m sorry I was late. It won’t happen again.”
▶️ Excuse: “I was late because my car wouldn’t start.”
▶️ Apology: “I’m sorry for the mistake in my report. I should have checked the
statistics more carefully.”
▶️ Excuse: “Well, if you hadn’t rushed me to finish the report, I wouldn’t have
made a mistake!”