How can I change my taxes after i already filed for 2020

You cannot. If your taxes are incorrect then you'll have to file an amended tax return. 

 

First, make sure you really need to amend and that your 2020 return was accepted in TurboTax Online or paper-filed through the mail. You can't amend a return that hasn't been filed yet.

1. Sign in to TurboTax.
2. Scroll down to Your tax return & documents (you may need to select Show), select 2020 and then Amend (change) return.
   • If you only see the option to amend 2019 or earlier, it's because you can't amend an unfiled 2020 return. Instead, just select Pick up where you left off, make your changes, and disregard the rest of these instructions.
3. Carefully follow the instructions. Don't worry if your refund changes to $0. This is normal on amended returns.
4. When finished, we'll give you instructions for printing and mailing your amended return as amendments can't be e-filed.

Three weeks after mailing your amended return, you can start tracking it at the IRS Where's My Amended Return? tracking tool.  Please allow at least 16 weeks for the IRS to process your amended return.

Processing times for amended state returns vary from state to state. If it's been more than 12 weeks since you mailed your amended state return, and you haven't heard anything, we suggest you contact your state tax agency.