If you need to add income and you have not yet submitted your return, you can go into Wages and Income, scroll down to find your specific type of 1099 form and then add the information into TurboTax.
If you
have already submitted your return: if
it gets rejected then you can
go in and make the necessary changes. If it is accepted, you will need to amend your return after you have
received your refund. The FAQ below will take you to a guide with the
instructions on how to amend.
https://ttlc.intuit.com/replies/7276605
