“if ”?

When you google for the meaning of “if“, you will find it has many meanings and different ways to use it.

One of the most commonly use of “if” would be introducing a conditional clause, or it means “in the event that”, for example, “if you have a complaint, write to the manager”.  For translation of these “if” sentences, we will use the basic meaning of “if“, that is, “如果”.

So “if you have a complaint, write to the manager”, we can translate it to “如果你有什么不满，可以写信向经理投诉”.

However, when “if” is placed in between words, there other meanings of “if ” applies, and it is no longer “如果”.

Another commonly use of “if” would be as “whether“.  For example, “he asked if we would like some coffee”.

So, what is the correct way of saying?