I don't understand what to put in for my "2017 tax liability for 2210 purposes." I do not have have this form in my last year's tax return.

If you have an Underpayment of tax in 2018, TurboTax prepares a Form 2210 for your return.

However, if this is the first year you owed tax, there are Exceptions to the Underpayment Penalty, which is why you are being asked for your tax liability from 2017. 

Look at your Form 1040 from 2017; if you owed tax, enter that amount; if you got a Refund, you could enter $0.

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https://ttlc.intuit.com/replies/4488009