The statement seems to have a small error in its wording. Typically, the government would lower taxes to shift the aggregate demand curve rightward, not increase them.
When taxes are reduced, households and businesses have more disposable income, which can lead to increased consumption and investment. This increase in spending can shift the aggregate demand curve to the right, indicating a higher overall demand for goods and services in the economy.
Conversely, if taxes are increased, disposable income decreases, which could lead to a reduction in consumption and investment, shifting the aggregate demand curve to the left.
Therefore, to shift the aggregate demand curve rightward, the government can decrease taxes or increase government spending. Both actions are intended to stimulate economic activity.