What do you think will happen to the potential energy of the ball if the mass of the ball remains the same and placed in a higher position?

Potential energy of the ball would increase

Explanation:

The formula for potential energy of an object is:

Potential Energy (object) = mass x gravity x height

In your question, the value for height is increased when the object (ball) is placed in a higher position. This creates a net positive change in the right-hand side of the formula and since the value of mass and gravity doesn't change because gravity is a constant (meaning it's always 9.8N/kg) and the mass is said to be kept the same, the ball's potential energy would increase.