Are you still working on your return or did you go all the way to the file process . If you sent it to the IRS already then you have to file an amended return after they complete their process.
If you are still open then go to the income section again and click on W2 section to add your additional income.
Disclaimer: Not a tax professional. Information gathered from internet links. Anything dated in June 2019 was posted in prior years and is before the 2019 limits and changes.
