この方法は適用範囲が広い。

English Translation

This method is of wide application.

The original translation is not so bad. But it’s a word-for-word translation. My alternative translation is:

この方法は応用が利きやすい。(おうようがききやすい)

応用する as a verb means “to apply (a method/technique/principle etc.) to other uses”. 利く means “to function properly and effectively”. やすい as an adjective means “be cheap”, but as an adverb it also means “be easily done”.
応用が利きやすい as a combined phrase means “it can be easily applied to a wide range of use cases”.