Field marketing is where grown-ups go out and talk to other grown-ups in person about things they want them to know about or buy. When companies want to sell products or services, they can't just wait for people to come to them in stores or online. They have to go out to where the people are and try to get their attention.
Field marketing is like when you have a lemonade stand on the sidewalk and you see people walking by. You might stand out front and say "Hey! Want some lemonade?" That's kind of like what a field marketer does, except they might be trying to sell you something else like a new phone or a vacation to a cool place.
The grown-ups who work in field marketing have special skills like being friendly and persuasive. They might have free samples or coupons to hand out to people to help persuade them to buy something. They might also have cool signs, bright colors, or funny costumes to help people notice them and remember what they're advertising.
Basically, field marketing is when grown-ups talk to other grown-ups in person to try to sell them stuff. It's like a lemonade stand for grown-ups.