"Will" is a very important, basic word in English. It's original meaning was "wish" or "desire". Now we use it in many ways. The word has become an important part of English grammar.

It is used in these main ways:

1. to talk about the future;
2. to express certainty;
3. to talk about decisions and willingness;
4. to make requests and orders;
5. to make an offer;
6. to be indirect and polite; and
7. to talk about habits.

We use reported speech (indirect speech) when we want to say words spoken by another person, or words that were said at a different time. Some examples are below:

Compare 'would' and 'will', 'can' and 'could' and 'may' and 'might' to understand them better. It is important to master these words, since often you can choose to use any one of them and what you say will still make sense. However, it might not be what you mean.