Curious about the idea of watermarking text. How would one go about embedding a watermark in plain text without altering its readability? Are there specific

Curious about the idea of watermarking text. How would one go about embedding a watermark in plain text without altering its readability? Are there specific techniques or tools designed for this purpose? To me it seems like a challenging task. Given the simplicity of text what methods could ensure the watermark remains intact? Perhaps there’s a way to subtly adjust character frequencies or patterns? That said I'd love from good sources to delve.