Annuity Start Date

If she has been receiving the pension for a while and has not calculated the non-taxable portion (assuming there is one), then it's normal to just omit those calculation. Some pension have an amount that tells you the non-taxable portion.

You can try to contact the pension admins or look back at prior tax returns.

I have done all of your suggestions and she did not make any desigations with her Fund Management company so they will not give any information.  Her previous tax returns that I am in possession of do not give that information.  I have the taxable amount but Turbo Tax is requiring that I include a Plan Start Date.  What if I get that answer grossly incorrect? 

Unfortunately, if you are trying to claim a non-taxable portion,  the program need the start date to keep calculations correct. If the return was done on TurboTax, you can enter the program and see if the date is included on the pertinent screen.