How can i add a text to document library without any file?

I would suggest you look on to the requirements first on what you are really trying to achieve, currently document libraries will need to have a document as an item before you can update its metadata.

How about maybe instead of document library, use a list, then add the files as attachments. You can use Pnp powerful library for list manipulations.

Or If you really would want it to be document library, you will need a 2 step process, on creating it in a list, then on approval or status / metadata change copy the list item to the document with the list metadata, more on combination of custom script and msflow.

Above is only a suggestions, so, Hope the concept helps on any way. Happy Coding! :)