Some embedded content (like Youtube or Vimeo videos) loads additional assets which are not necessary on initial pageload. You can lazyload them, so iframes will be loaded only before they arrives in the viewport. You can set the Preload Sensitivity to control when would you like to start preloading iframes.
Exclude Iframes by URL
You can exclude iframes from being lazyloaded. You can use full or partial URLs here.
Exclude Iframes by CSS classname
You can exclude iframes with CSS classnames as well. Use only the classname without the leading dot.
Respect Lazyload Standards
If you enable this option iframes which has skip-lazy classname or data-skip-lazy attribute will be excluded from lazyload.
Load Iframes on User Interaction
You can also load iframes only after the first user interaction (mousemove, keypress, touchstart or scroll).