Then you need to file an Amended return to add it. Was your first return Accepted?
You should not amend until the first return has fully processed and you get the first refund or your tax due payment has cleared. But first be sure to save a copy of your original return since the amended return will overwrite it.
You can find Amend under
Federal Taxes or Personal (for Home & Business)
Other Tax Situations
How to Amend this year
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-federal-tax-return-current-year/L7eS6o1qh_US_en_US