If you haven't filed your 2023 return yet, you can still change your filing status and add your spouse in TurboTax. You can go to the "Personal Info" tab and find the option update your marital status and filing status. Then you can add his income and deductions.
If you've already filed your return, you'll need to file an amended return (Form 1040-X) to change your filing status to Married Filing Jointly and add your spouse's personal info, income, and deductions.
See TurboTax Support article: How do I amend my federal tax returns?
