These two punctuation marks are pretty easy to understand. Just don't ask me to explain why one is a "mark" and the other is a "point."
Use question marks at the end of questions, and exclamation points at the end of exclamatory sentences. So far, so good. Want a few examples? You got it.
What was he doing? Was she wrong? These are clearly questions, so you need the question mark. But let's rewrite the sentences a bit. She wondered what he was doing. She asked if she was wrong. Although these sound like a question, they aren't. They are indirect questions and do not need question marks. What was he doing? she wondered. Yes, you're seeing right. That's a question mark in the middle of a sentence, and it's correct. Notice there is no comma.
A one-word question doesn't need a question mark: My dad said I couldn't go. I asked him why. You could also say I asked him why not and still not need a question mark.
Exclamation points are even easier. Use them to express an emphatic or strong emotion, like anger or surprise. Danger, Will Robinson! Oh, you startled me! Sometimes a sentence that is a question in form, like Why do computers hate me? is really an exclamation, and should be punctuated so. Why do computers hate me!
In order to be effective, exclamation points should be used with restraint. How many times a day are you really scared or really surprised? Let your text convey the emotion. Can you use both a question mark and an exclamation point