There isn't just one tax rate. Different types of income are taxed at different rates. And income of one type is often not all taxed at the same rate because it spans more than one bracket.
The tax rates are not shown on the tax return.
Why are you asking about your tax rate? If you just want to get an idea of how much of your income is going to taxes, divide your total tax on Form 1040 line 24 by your Adjusted Gross Income on Form 1040 line 11. (These line numbers are for 2021.) That will show you the overall percentage of tax you are paying on your income. If you are trying to figure out what tax rate would apply to additional income, that's more complicated. It depends on the type of additional income, and on the base amount of income that you have before the addition.
