As explained in previous parts of the task, the pendulum converts its potential energy into kinetic energy back and forth as it swings.
The pendulum reaches its maximum height when all its energy is stored as potential energy, point at which its velocity is zero. Then, the pendulum goes down and reaches its maximum speed when all its energy is stored as kinetic energy at the lowest point of its trajectory.
Since potential energy depends on the height of objects with respect to a reference level, the pendulum will have greater potential energy the higher it is located.
Then, to give the pendulum more energy, you need to raise it to a higher point before releasing it, or give the pendulum a greater velocity.
Therefore, the answer is:
You can give the pendulum more energy by raising it to a higher altitude before releasing it.