This year in the 2024 Turbotax Windows version (not online) under Business/Business Expenses/Other Common Business Expenses go to Employee Expenses, then Pension Plan Startup Costs. The description states "Pension plan startup costs include the expenses to: Establish an eligible employer plan, Administer an eligible employer plan, or Educate your employees..." I entered $125, which is the yearly admin fee for the solo 401K I have (mysolo401.net). After that it asks questions about the plan. Under "We need a little more info about ...startup costs" I clicked YES for "Did you provide and auto-enrollment option...". It then added the $500 tax credit on form 8881.
I didn't try this on the 2024 online version - maybe it works there?
Last year I used the Windows version and edited the PDF, adding form 8881. I couldn't submit the return electronically so I mailed it in.
