Just like the part of speech 'noun' naming the main actor of a sentence, A noun clause is a subordinate clause that is used as a noun within the main clause of a sentence.
You can use a noun clause as a subject, a direct object, an indirect object, an object of a preposition, or a predicate nominative. EG 'Whatever you can learn about computers' will prove useful in the workplace. [noun clause as subject] You should take 'whichever computer classes are offered.' [noun clause as direct object]
EG The instructor gave 'whoever was available' word-processing lessons. [noun clause as indirect object] You can get by on 'what you learn in this class.' [noun clause as object of the preposition] The basics of computers is 'what you must learn.' [noun clause as predicate nominative]
The following are some words that can be used to introduce noun clauses. (How, however, if, that, what, whatever, when, where, wherever, whether, which, whichever, who, whom, whoever, whomever, whose, why.
Sometimes the introductory word id dropped from a noun clause. I think 'computers will be even more important in the future [That has been omitted from the beginning of the clause.]