Create your own kind of “Creator Documentation”?

Of course. In C# you can do this, for example

/// 

/// Dies ist die Beschreibung.
/// 
/// 
/// Ein paar Hinweise
/// 
/// Eine Beschreibung für diesen parameter.
/// Eien Beschreibung für den Rückgabewert.
public int EineMethode(int parameter)
{
    // code...
}

This format can be applied in C# to anything possible and as soon as you hovert somewhere in the IDE about it the description will be displayed.

What you probably meant was a documentation of it on a website like this on Microsoft https://learn.microsoft.com/de-de/dotnet/api/system.io.file?view=net-8.0. Such documentation can thus also be generated in part.

In each language, the format in which you can understand method, etc. for the IDE is somewhat different. This is done, for example, in JS and TS:

/**
 * Eine funktion
 * @param {number} parameter - Ein parameter
 * @returns {number} Das Ergebnis
 */
function eineFunktion(parameter) {
  // code...
}

lg Suiram1