Gravitational force of attraction exists in all the places in the universe. This is the force of attraction between any two substances that are having a mass of their own.
Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them.
The weight of a body placed at the centre of the earth is zero. This is because acceleration due to gravity is zero at the centre and hence weight (mg) is zero at the centre. Thus, both statements are true.