Hi, I don't know how to find U.S tax code (section code) for each line of the individual income tax Form 1040 (Form 2017)

Please help.

7 Income 8a 7 8a b 9a b 9 Attach Form(s) W-2 here. Also attach Forms W-2G and 1099-R if tax was withheld. . 10 11 12 13 If you did not get a W-2, see instructions. . Wages, salaries, tips, etc. Attach Form(s) W-2 . . . . . . . Taxable interest. Attach Schedule B if required . . . . Tax-exempt interest. Do not include on line 8a. 8b Ordinary dividends. Attach Schedule B if required ... Qualified dividends . . . . . . . . . . . 9b Taxable refunds, credits, or offsets of state and local income taxes . . . . . Alimony received . . . . . . . . . . . . . . . . . Business income or (loss). Attach Schedule C or C-EZ . . . . Capital gain or loss). Attach Schedule D if required. If not required, check here Other gains or (losses). Attach Form 4797 . . . IRA distributions. 15a b Taxable amount . . Pensions and annuities | 16a b Taxable amount . . . Rental real estate, royalties, partnerships, S corporations, trusts, etc. Attach Schedule E Farm income or loss). Attach Schedule F. Unemployment compensation . . . . Social security benefits 20a | b Taxable amount b Taxable a . . . Other income. List type and amount Combine the amounts in the far right column for lines 7 through 21. This is your total income 11 12 13 14 15a 16a 17 18 19 20a 21 22 . 14 15b 16b 17 18 19 20b 21 22