How

How is a wh- adverb which we use in wh- questions, exclamatoins, and for introducing subordinate clauses. It's the only wh- word which is not spelled with a wh- , for example, who, what, when, why, where, etc. It has many uses.

1. How asks a question about means, manner, or instrument

How means "in what way", "by what means?"

Example: "How was he driving the car?" "Dangerously. Like a madman in fact!"
Let's see other examples below:
How do we get from here to the City Hall? (asking for directions)
"How are you travelling?" "By plane, and then by boat."

2. How also asks for our feeling or opinion about something

2.1. How acts as an adverbial

How acts as an adverbial (adverb of degree) with verbs such as like.
"How did you like the party?" "Very much."

2.2. How acts as complement

How acts as complement with be, feel, look, seem, appear, sound, smell, taste.
"How is your leg? I hear you broke it when you went skiing." "Much better, thank you."

3. How with an adjective, an adverb, or a quantity word

How also comes before an adjective, an adverb, or quantity word, in asking questions about degree, distance, frequency, and length of time.

3.1. How before adjectives (degree)

Examples:
"How old are you?" "Nearly thirty."
"How tall are you?" "About six foot."

3.2. How before adverbs

3.2.1. Degree

"How soon does the next train leave?" "In 20 minutes."
"How well can you speak French?" "Not at all well - I'm only a beginner."

3.2.2. Distance: how far?

"How far is it to the next garage?" "Less than a kilometer."

3.2.3. Frequency: how often?

"How often do you visit the dentist?" "I go for a check-up every six months."
"How often is there a flight to California?" "Five times a week."

3.2.4. Length of time: how long?

"How long are you going to stay in Texas?" "For three weeks."
"How long will the meeting last?" "About two hours."

3.3. How before quantity words: how much? how many?

"How much does that t-shirt cost?" "twenty-five dollars."
"How much gasoline (U.S.) / petrol (G.B.) did you put in the tank?" "five gallons."
"How many people voted for the motion?" "145."

4. How with exclamations

How (as an adverb of degree) also introduces exclamations.
How silly these latest fashions are!
How I loved that little dog! (= I loved him very much indeed.)

5. How + about

How + about frequently introduces suggestions in conversation.
How about going to the disco tonight?
How about a cup of tea? Would you like one?

6. How in greeting

We often say: Hello, how are you? when we greet somebody.

Note: We do not use how after way. Say:
The way we speak is completely different from the way we write.
NOT: The way how we ... the way how we write.

I hope this article helps. If you have any question, please leave a comment in the comment section.