Door-to-door

"Door-to-door" means going from one person's house to another person's house to sell something, give information or ask for something.

So imagine you're at home and someone comes knocking at your door. They start talking to you and trying to sell you something, like a vacuum cleaner or a new phone. They might also ask you questions or leave something for you to read later.

That's called "door-to-door" because they're literally going door to door, trying to talk to as many people as they can. It's a way for them to reach out to people who might not be looking for what they're selling or might not have heard about it yet.