Extraposition moves a heavy subject clause to the end of the sentence, using it as a dummy subject in its place: It is remarkable that… / It is impossible to… / It seems that… / It turned out to be… This structure is preferred in formal writing because it front-loads the key evaluation and postpones the detail.
Extraposition postpones a heavy subject clause to the end, using 'it' as a dummy subject. Choose the correct extraposition form.
Extraposition postpones a clause (that-clause, to-infinitive, gerund) to the end of a sentence and inserts dummy it in subject position. This is the default in formal English, where heavy subjects at the start are unusual.