Itemized and Standard Deductions on 4(b) of W4

Question

I'm filling out a W4 and in 4(b) it asks for "an estimate of (my) 2020 itemized deductions (from Schedule A( Form 1040 or 1040-SR). Such deductions may include qualifying home mortgage interest, charitable contributions, state and local taxes (up to $10,000), and medical expenses in excess of 7.5% of your income)

I see on line 12 of my 1040, it has an amount and to the left it says it's "Standard or Itemized Deductions (from Schedule A)"

My Question: On the W4 it says "Enter an estimate of your 2020 itemized deductions but on the 1040 it says the amount on line 12 is "Standard or Itemized" and I don't see anywhere on that document that has an amount for just itemized, should I go ahead and put the number from line 12 on my W4?

Also: Line 4 of the same W4 asks for "an estimate of your student loan interest, deductible IRA contributions, and certain other adjustments (from Part II of Schedule 1 (Form 1040 or 1040-SR)) but I don't see anything on my 1040 that it refers to as "Schedule" or "Part II" so I don't know what amount I'm looking for.

Answer 1

If you look at the worksheet on page 3 (assuming you're using the current W-4 form) you'll see that you eventually subtract the standard deduction from this total amount, so you could just put 0 and you'll get to the same result as if you use the standard deduction.

For line 4, those schedules are filed in addition to the 1040. If you didn't file those, then put 0, meaning you didn't deduct any of those items.

That section of the form is trying to determine how much you have in deductions above the standard deduction in order to determine the appropriate amount of tax to withhold.