How to delete redundant text files?

I have numerous text files, many of which are no longer needed. How do I delete these files ?
OS 11.1

What is OS 11.1 - do you mean macOS 11.0.1 (Big Sur)?. If yes - open Finder and Right click -> Move to Trash

If you want 'em additionally to disappear from right pane of LibreOffice’s Start Center, hover your mouse over the icon, watch for the cross in the upper right corner on the thumbnail and click the cross (This doesn’t remove a file from your system, but removes the reference to the file from LibreOffice. In non-technical words: This action removes LibreOffice’s knowledge of having opened that file in the past).

You don’t delete files from LibreOffice (or from MS Word, for that matter). You open the file manager, navigate to the folder where your redundant files are chilling, and delete them then and there.

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Use the file manager app that comes with your system. Which app that might be, depends on the make of your “OS 11.1”. For the purpose of limiting my answer, I guess that your OS would be MacOS 11.1 (aka “Big Sur”) since for MacOS this is the latest (or “current”) version, and also (in my experience), most users of other systems know the name of their OS and realize that it is significant. I apologize if my guess is wrong.

For MacOS, the file manager of choice is Finder. Open it from the square happy face on the dock, or keyboard shortcut Cmd+Option+Spacebar.

Open Finder to your Documents folder, locate your documents there by name, and delete them (drag to the bin on the far right end of the dock).

Even when you delete them, files will remain in the “recent documents” list. There is an option below that list (bottom element of the menu) to clear the list.

There is no way that I know of to “refresh” the list, for maintaining only files that are currently available.

Thanks to @anon73440385, I now know. See his comment about manual removal in the start center.