My wife had a little bit of income from babysitting in 2019 that I didn't even think to put on our '19 return. How would I go about fixing this?

[crisisbringer]

It's a very minor amount relative to my pay so I don't expect it would change much, but she went and claimed it for unemployment when COVID hit and she was unable to babysit anymore so she brought it to my attention as something that might need to get added to our previous tax return.

[JeffreyR77]

You can amend your tax 2019 tax return to add this income and calculate the additional tax owed. 

A change to your Federal tax return also will require an amended state return.

There is no penalty for identifying income that you omitted by accident.

Amended returns have to be mailed in.    How do I amend a 2019 return in TurboTax?