SEO & Posting the same pages on different domains without copying the site & iframe

[mrbeansbigtoe123]

Good evening... Let me elaborate on the issue I am questioning briefly... What could be the ways to publish some/all of the pages I have published within domain1.com on domain2.com and domain3.com without falling into the category of duplicate sites, without getting banned by search engines, and without wasting the domains? To what extent would having the same owner for all domains and the absence of any complaints be a saving grace? What are your opinions on displaying the pages within iframes? I would appreciate it if you share, thank you...