Every object that has mass is surrounded by a gravitational field. A field is a region where a force acts on an object without anything touching it. Any other mass that enters the gravitational field feels a force of attraction towards the object. This force always pulls masses together. It never pushes them apart.
All matter has a gravitational field, including a pencil, a person and a mountain. The strength of the field depends on the mass. The field of a small object is so weak that the force on a nearby object is far too small to notice. The field of a very massive object, such as a planet or a star, is much stronger, so the force of attraction is much greater.
This is why the Earth pulls you towards its centre, but you do not notice the pull of the person next to you. The Earth is very massive, so its gravitational field strength is much greater than theirs.
