The answer is Increase and Decrease W-4 allowance is deducted directly from the total of your salary by the employers.This means that the amount of money that you could take home will be reduced. Since the employers now in the possession fo a certain percentage of your income, the tax burden is now no longer in your hands, which will reduce your amount of tax payment.
Sorry But there is no shape for me to look at to give you the answer :( Edit the question or just send me a screen shot of it in discord, mine is Mousycritter#2842