Generally, you do not report contributions to your 403(b) account (except Roth contributions) on your tax return. Your employer will report contributions on your Form W-2 Wage and Tax Statement. Elective deferrals are reported in Box 12 and the Retirement plan box will be checked in Box 13. If you are a self-employed minister or chaplain, see the discussions below.
Per IRS Publication 571 regarding Tax-Sheltered Annuity Plans (403(b) Plans), on page 4:
Self-employed ministers. If you are a self-employed minister, you must report the total contributions as a deduction on your tax return. Deduct your contributions on line 15 of the 2020 Schedule 1 (Form 1040).
To enter the deduction in your TaxAct® return:
Refer to IRS Publication 560 Retirement Plans for Small Business to determine the contribution amount that can be deducted on Schedule 1 (Form 1040) Additional Income and Adjustments to Income, Line 15.
Chaplains. If you are a chaplain and your employer doesn’t exclude contributions made to your 403(b) account from your earned income, you may be able to take a deduction for those contributions on your tax return.
However, if your employer has agreed to exclude the contributions from your earned income, you won’t be allowed a deduction on your tax return.
If you can take a deduction, include your contributions on line 22 of the 2019 Schedule 1 (Form 1040 or 1040-SR). Enter the amount of your deduction and write "403(b)" on the dotted line next to line 22.
To enter this in your TaxAct return:
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.