I filed my tax return in the beginning of the year but i forgot to enter one more W-2. I already got my return and used it so what do i do ?

Amend the return.

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-federal-tax-return-current-year/L7eS6o1qh_US_en_US?uid=ley8tz1g

Yes, you need to amend your return and add the additional W-2 form. Since you have already received your refund, you can go ahead and start your amendment as soon as you are ready.

Here's how to get started:

1. Sign in to TurboTax.
2. On the home screen, scroll down to Your tax returns & documents and select 2023.
3. Select Amend (change) return, then Amend using TurboTax Online.
4. Carefully follow the directions to start your amendment.
5. Your refund will go to zero, don't worry, that's normal.
6. On the screen OK, let's get a kickstart on your amended return, select the reason(s) you're amending and Continue.
7. When you reach Here's the info for your amended federal return, select Start next to the W-2 section.
8. Continue through the screens, make the changes you need to make, and carefully answer the remaining questions to finish amending your return.