An <iframe> element is a pretty basic element with very few options.
It has one main goal in life, which is to display the contents of the site you specify in src="", in the location on your page you've positioned it.
Unfortunately, due to the way the Internet and browsers have evolved, IFRAMEs have quite a few peculiarities and browser-specific behaviors.
Sometimes the IFRAME itself is in that snippet, and you can change some aspects- sizing, scrolling behavior, border. Often, today, it's not.