How to make a code which creates a new HTML document and inserts it into an <iframe> in the current document.

Answer 1

In HTML insert your inner html source inside iframe. If you mean with js, see https://www.w3schools.com/jsref/prop_frame_contentdocument.asp

Answer 2

https://code.sololearn.com/WD0R9doZ6hwz/?ref=app