If my spouse is a non residential alien, what deduction should I choose?

When married filing separately, if one spouse itemizes, then both spouses must itemize, even if spouse #2 does not have any deductions (forcing them to take an itemized deduction of zero).  It is not allowed to stack up all the itemized deductions on one spouse and have the other spouse claim the standard deduction. This is an important consideration when two US spouses decide whether to file jointly or separately.

But since your spouse is an NRA, they only file a tax return if they have US-source income.  If there is no US-source income, then you can choose whichever is best for you—itemized or standard—because your choice will have no financial impact on your spouse because your spouse won't file.

If your spouse does have US source income, then you will need to think about their tax return (1040-NR) and what their deductions might be, and whether you will be better off both taking the standard or both itemizing.

Note that Turbotax can't prepare a 1040-NR for your spouse (if they have US source income); you would need to find another tax preparer or software company. 

It depends. According to this Turbo Tax article, here is how to file the return. If you choose Married Filing Separately, you don’t have to include your spouse's income on your return, and therefore you won’t have to treat your spouse as a resident for tax purposes. However, you’ll have a lower standard deduction and you may not be able to claim other certain tax benefits.

You don’t need to apply for an ITIN or Social Security number for your spouse, but you must print your return and file by mail.

1. Prepare your return in TurboTax.
2. When you get to the Let’s get ready to e-file screen, select File by Mail.
3. TurboTax will give you an error regarding the missing Social Security number or ITIN for your spouse. Proceed to print with the error, but write Nonresident Alien or NRA in the space for your spouse’s Social Security number before mailing in your return.
4. Mail the return to the address on the instruction sheet that prints with the return.

To file electronically in the future, you’ll have to complete a W-7 form and attach it to your return as explained under Married Filing Jointly with a nonresident alien spouse above.

As far as itemizing your deductions, you may itemize if your itemized deductions exceed the standard deduction amount. For Married Filing Separately, your standard deduction is 12,550 for tax year 2021. However, if you live in a community property state of Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, and Washington, you will need to allocate the your income and deductions 50/50 between you and your spouse, even if your wife does not earn income. If this is the case, you may not have enough itemized deductions to deduct.

You might wish to file jointly. If so please refer to the following Turbo Tax link and select the option that says "Married Filing Jointly with a non-resident alien spouse and follow the instructions. This may be helpful if you live in  Community Property State.