I owe for 2019 that I was unaware of. My 2019 W2 line 12a shows 0. my e-filed 1040 shows line 12a as $6963.00. Is this a normal addition? Ido not collect tips

[Mike9241]

we don't know your complete situation. If your w-2 should zero for box 12 code A you should not owe the fica taxes on uncollected tips. 

you have to be careful on the w-2 there is box 12a, 12b, etc but in the box there's also a code letter.

Box 12d could show code A.

that number does not appear by magic. only you make entries for your return. So why $6963 would show up in your efiled return is unknown. 

Check your w-2 transcript with the IRS or call them  

https://sa.www4.irs.gov/secureaccess/ui/?TYPE=33554433&REALMOID=06-0006b18e-628e-1187-a229-7c2b0ad00... 

if it doesn't show the amount and you got a notice from the iRS about owing taxes due to that entry follow the instructions for disputing the bill. This would be best served by preparing an amended return without that amount and sending it with the notice. be sure to sign and date it and use a tracking service

[VolvoGirl]

W2 line 12a is different than your 1040 line 12a.  W2 box 12a is for deductions like health ins or 401k deductions.  Nothing to do with 1040 line 12a.   On your W2 box 2 is for federal income tax withholding.  That is what's important.

For 2019 1040 line 12a ($6,963?)  is the tax on all your income.  How much is your taxable income on line 11b?   Then the withholding from W2 box 2 is subtracted on line 17.   You either have a Refund on line 20 and 21a or a Tax Due on line 23.

Did you file a 2019 tax return?  Did you pay the tax due on it?    Or did the IRS change your return?