Receiver (Document):?

Short answer: The Document class represents the receiver of the command. It contains the actual operations for adding and removing text from the document. The AddText and RemoveText methods manipulate the internal content (a StringBuilder).

Example code

public class Document
{
private readonly StringBuilder _content = new StringBuilder();
public void AddText(string text) => _content.Append(text);
public void RemoveText(string text) => _content.Remove(_content.Length - text.Length, text.Length); public override string ToString() => _content.ToString();
}

Real-world example (ShopNest)

Use a GoF pattern in ShopNest only when it removes duplication or makes a change safer—explain the problem it solves in the interview.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.