Some people generate copyrightable works, which naturally enough they then own the copyright to. However, to allow general re-use of those said works, said people may oft-times attach to said works a Creative Commons declaration, which grants certain rights to re-use said works to persons in general.
This
can have certain advantages, e.g. for spreading pernicious or otherwise self-promoting ideas, which people would otherwise hesitate to share due to fear of copyright infringement; also to save the content creator from being inundated by irritating plebian requests for irrelevant reuse of trifling works for boring reason.
To save having to laboriously attach creative commons or similar metadata to every piece of copyrightable work you generate, there could be a general waiver which you could publish.
Something along the lines of "I hereby declare that all copyrightable works generated by me in the past or in the future are hereby released under a CC BY SA NC license unless indicated otherwise" could be used, though I am sure that a crack team of lawyers could draft a better version for a modest fee.