When you assign a license to your work, you set the terms for how others can use it. If you don't want it being reused, you don't have to do anything. You already own the copyright.
But if you do want to share you have options for what you allow others to do without requesting explicit permission.
Creative Commons licensing allows information creators to openly share their work (and others to reuse it), as long as the use of that information complies with the selected license.
And when you are the content creator YOU get to decide whether to license your work and what license to use to share your work!
Find out more at creativecommons.org
But what if you don't want to reserve any of your rights?
After enough time has passed, all works eventually pass into the public domain (which means there are no restrictions on their use). But if you want to opt out of your rights as a creator, then CC0 allows your work to pass into the public domain.
"CC0 (aka CC Zero) is a public dedication tool, which enables creators to give up their copyright and put their works into the worldwide public domain. CC0 enables reusers to distribute, remix, adapt, and build upon the material in any medium or format, with no conditions."
--https://creativecommons.org/publicdomain/zero/1.0/