How do i file 2019 taxes that involves back pay for ssdi

SSDI benefits, like other Social Security income, must be reported on your tax return. Whether you pay tax on those benefits depends on your total income and benefits for the year.  To report your SSDI, see the following answer from Michael L1:

 

You report the Social Security disability income in the Income & Wages section of TurboTax.  Your Social Security Disability will be on a Form SSA-1099.  

Any SSA-1099 form, gets entered the same way:

1. Open your tax return in TurboTax online.

   (To do this, sign in to TurboTax, see your Tax Timeline, and click ‘Take me to my return.’)

2. Using the Search feature in the upper right corner of the screen, enter SSA-1099 and perform the search. Then click on Jump to SSA-1099, which is the first item in the search results.
3. Select Yes, let's work on Social Security benefits and click Continue.
4. Check the first box, Form SSA-1099.
5. Enter the amounts for yourself and your jointly-filing spouse, if they received an SSA-1099 also.
   • SSA-1099s for children and other dependents are not reported on your return. They should report it on their own return, but only if they're required to file a return for some other reason (this is uncommon).
6. Click Continue. 

TurboTax will automatically calculate what portion, if any, of your Social Security benefits are taxable, if any.

 

Social security benefits include monthly retirement, survivor and disability benefits. They don't include supplemental security income (SSI) payments, which aren't taxable. The net amount of social security benefits that you receive from the Social Security Administration is reported in Box 5 of Form SSA-1099