Both of these phrases are correct, but only one of them can be used to form a question. When we want to ask how something works, we say, how does it work? When we want to answer this question, we say, how it works is like this…
Therefore, one phrase is used to form a question, and the other phrase is used to answer the question.
Why is the question format written differently?
The question form needs the verb “do.” This is because we are basically asking how a certain item does something. There are alternative ways to ask the same question, but they all contain the same verb.
What does it do?
What does he do with it?
How do I make it work?
How does it work?
We use “do” to describe the accomplishment of action, and we use “does” to refer to the accomplishment by someone or something else. These sentences all refer to either of these functions.
Why does the answer format not need a verb?
The answer format does need a verb, but just not the verb “do”.
How it works is a phrase or a sentence fragment (rather than a complete sentence such as a question). We use it when we are giving information about something, and we have just gotten to the part about how it works.
…..then finally, you plug the printer in and switch it on. How it works is by receiving information from your computer wirelessly….
Now, how it works is that your feet push down on the pedals, which rotate and propel the bicycle forward.
Notice that, as a sentence fragment, how it works can appear in different places in the sentence, and that it is often used to direct specific information.
Can “how it works” be used to form a question?
The phrase “how it works” can be used within a sentence to help form a clear question. It just doesn’t form a question on its own.
Can you tell me how it works?
Will you show me how it works?
Does anybody here know how it works?
The question format how does it work and the sentence fragment how it works appear almost identical. However, one is a complete sentence in the form of a question and the other is a phrase and can only be used within sentences.