Estimated tax payments are made directly to the IRS and do not go through your employer. Estimated tax payments have nothing to do with the W-2 from your employer, so your employer cannot enter any of your estimated tax payments. All federal income tax you had withheld by your employer will show on your W-2 in Box 2 You can make the extimated tax payments by mail using form 1040-ES or electronically on the IRS website. I make my estimated tax payments through the IRS website and can see how much and when I made estimated tax payments on the website once I sign in. I hope this helps.
Your W-2 won't tell you if you made estimated tax payments, but it will tell you how much state and federal tax was withheld from your check each payday. [Estimated payments are usually quarterly payments made when you don't have taxes withheld from your paycheck, or are self-employed.]
On your W-2:
If you did make quarterly estimated payments, you can check your account on the IRS website Pay Your Taxes and the MO Department of Revenue.