About posting books or articles online...

..Is there any way to prevent people from taking credit for unpublished written work just like how you can put a watermark in pictures (like the one I have attached)?

https://www.booksie.com/

Here's their page about copyright:
https://www.booksie.com/member/guide/copyright-policy

No matter what, if you put it out on the internet, that does open you up to others stealing your work. This goes for writing, drawing, music, etc. You put it out there, someone may take it. You can claim copyright to your work if you see someone else taking credit for it, sending a cease and desist, reporting them to their host website, taking them to court if necessary. But taking those actions are entirely up to you.

>>2685988
No. It's text. You can make it more difficult for people to steal it by say, making it an image rather than plain text, but there are loads of programs out there that can pull text off of images, or if someone is really dedicated, just transcribe it back into plain text.

Even if you published pure audio of it someone could just transcribe it.

If you're THAT paranoid of your ORIGINALCONTENTDONOTSTEAL, either get a publisher who will fight to defend the copyright, or be prepared to fight it yourself (read up on copyright laws, prepare a formal cease and desist etc.)

>>2685988
If you think your work is that amazing that someone would bother to try to steal it, why not just publish it?

Kindle Direct Publishing
https://kdp.amazon.com/