You get to e-file ONCE--and all of your W-2's are supposed to be on the same tax return. Since you did not do that, you will have to wait for the original return to be fully processed then prepare and mail in an amended return to add the other income.
How do I amend my 2019 TurboTax Online return?
The 1040X becomes available late in February, so you have to wait for it. If your return is still being processed now, it would not be a good idea to amend yet anyhow. Sending in an amended return while they are still processing your original return could cause confusion that would delay your refund for months.
Check back later for the 1040X. AFTER your return has been fully processed.
A 1040X cannot be e-filed. It must be printed and mailed. It will take about 4 months for the IRS to process an amended return. It is a good idea to use a mailing service that will track it, like UPS or certified mail, so you will know it was received.
Wait about 3 weeks from mailing and you can check the status of your amended return:
https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1
https://ttlc.intuit.com/questions/1908543-do-i-need-to-amend
https://ttlc.intuit.com/questions/3318997-how-does-the-refund-math-work-on-amendments