How do I start my husbands return for his 2023 return for 1099-NEC?

[DoninGA]

If he was self-employed in 2023 and received a 2023 Form 1099-NEC then he needs to amend the 2023 tax return that was filed to add the income from 1099-NEC.

See this TurboTax support FAQ for amending a prior year tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...