I already claim and received my Tax return from my first job, but i forgot to claim my w-2 from my second job, what shoul i do ?

[VolvoGirl]

You have to file all your income on the same tax return.

If you need to add another W2, 1099 or more info or correct something on your first return that has been Accepted you have to wait until it has been fully processed and you have received your refund.  THEN you can prepare an amended tax return 1040X and mail it in. You cannot e-file an amended return.  Meanwhile, DO NOT change anything on your return until you start the amended return.  If you did change or add the missing info then take it out and put your return back to the way it was when you first filed it.

The Amended 1040X form won't be ready until Feb. 5, 2020.

How to amend an Online return

https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-turbotax-online-return/00/27577