You asked: "How long does TurboTax take to process by mail?"
You may need to explain more about what that means. Are you wanting to file your returns by mail, or are you asking about getting a Federal refund check in the mail after filing?
If you are filing by mail, why are you doing that instead of efiling? Efiling is normally best. If you haven't already mailed the return and still want to efile, we may be able to help you do so.
Otherwise, are you planning to print, sign, and file your return by postal mail instead of efiling? If so, TurboTax does not mail it for you. YOU have to do the printing, signing, mailing, etc. It's recommended to mail by a method that has tracking such as certified mail, priority mail, etc.
It takes the IRS about 6 weeks to process your return and deliver a Federal refund to you when one has filed by mail. You can choose to receive the refund by direct deposit or a check in the mail.
After 4 weeks from mailing ,it should show in the IRS "Where's My Refund" tool here:
https://www.irs.gov/refunds
