Depending on the state, the amount that it's asking for might not be in one place in the previous year's tax return. You have to add up a bunch of different amounts to get the total. Click the blue link that says "What does this include?" It will give you a list of what things to add up. It's basically any state tax payments that you made for 2018. The most common would be state withholding, and possibly state estimated tax payments. Since you're dealing with your wife's refund, and entering only her information, I would enter only her state tax payments for 2018. From some of the screen shots that you posted, it appears that your wife's refund is from California. If so, I think that line 76 on her 2018 Form 540 is probably the amount that you should enter.
This question in TurboTax asking for the "total of all your payments and withholding" is very mysterious. It's not clear why it asks the question. The amount is not needed to calculate how much of the refund is taxable. And, in fact, TurboTax does not appear to use the amount for anything. I tried to get an explanation from TurboTax a few years ago, and never got a satisfactory answer. So don't knock yourself out worrying about getting the total exactly right. It apparently doesn't matter what you enter. It probably doesn't affect anything.
