S election effective date

I don't think turbotax is going to let you enter an effective date that's before the incorporation date. You'll have to override or something.

Please double check your dates.

Generally, you would create the corporation (incorporate) first and then elect to be taxed as an s corporation after that.

Either the two dates would be the same or the s election should come after the incorporation date.

You can't elect to be an s corporation if you have not created the corporation first.

I don't understand what date is entered as: 01/101/2019?  Is it the 10th, the 11th, or the 1st of January in 2019?

Then, if the legal documents show that the S election happened before the initial incorporation, then it could be that they filed Form 2553 to actually create the corporation and elect to be an S corporation at the same time.  

A corporation or other entity eligible to elect to be treated as a corporation must use Form 2553 to make an election under section 1362(a) to be an S corporation. An entity eligible to elect to be treated as a corporation that meets certain tests discussed below will be treated as a corporation as of the effective date of the S corporation election and doesn’t need to file Form 8832, Entity Classification Election.

If that is the actual situation, then you would use the date of the Form 2553 to be the date of incorporation and the date of the s election.