You can choose to contribute to regular deductible 401(k) or Roth (non-deductible) 401(k). It is still employer-sponsor plan. The limit is the same for both types of 401(k). For 2021, the limit is $19,500 for people under age 50, $26,000 for those age 50 or over. For 2022, the respective limit is $20,500 and $27,000. You can contribute to both but the total is limited to $20,500/$27,000.
Roth 401(k) is not the same as the Roth IRA account.
If you contribute to Roth 401(k), the contribution is included in your taxable income (reported in Box 1 of Form W-2), and if you contribute to regular 401(k), the contribution is excluded from your income already, you can not take a deduction when filing your taxes. In this case, you don't add it under Deductions and Credtits in TurboTax.
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