I want to claim my son how I add him

Under Federal Taxes, Deductions and Credits, You and Your Family, Child and Other Dependent Tax Credit

If you need to revisit the Dependents section in TurboTax Online, here's what you do:

1. Open or continue your return in TurboTax, if you aren't already in it.
2. Select My Info in the left navigation.
3. Select the Add a dependent button if you need to add someone.