I'm wondering how - if you created something that is potentially patentable - would you "protect" it? Not protect in the sense of "ensure a revenue stream" but

I'm wondering how - if you created something that is potentially patentable - would you "protect" it? Not protect in the sense of "ensure a revenue stream" but protect in the sense of "ensure it's available royalty-free for any future users"? From what I understand, Licenses (MIT/Apache/GNU) are different than Patents, so it seems that just licensing it wouldn't work. Can you receive a patent and then immediately put said patented idea into the public domain?