Can I file an amended claim with Turbo Tax if I file an original return with H&R block? Big mistake filing with H&R block.

Yes, you may use TurboTax to amend your income tax returns even if you prepared them with another tax preparer. Please note that the instructions assume that you prepared your return using TurboTax.

 Since you did not, you will have to enter the information from your return as originally filed.  To amend your prior year income tax return(s), click on How to amend (change or correct) a return you - TurboTax Support

After you prepare your amended return and are ready to mail Form 1040X - IRS.gov Amended U.S. Individual Income Tax Return, you should include the following forms:

• The new (amended) Form 1040
• Any forms or schedules that were added or changed as a result of preparing the amendment
• TurboTax will guide you on what forms to print.

Please note that 1040-X cannot be e-filed - you will need to mail a paper return.  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.

The mailing address for your state and tax situation can be found on the Form 1040-X Instructions.  Go to page 14, Where to File. 

If you also need to amend your state income tax return, click I need to amend my state 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.

[Edited 3-10-2020|1 pm PST]

there is a big mistake on my tax

If you have not filed your return, you may sign back into TurboTax and make any necessary adjustments.

If you have already filed your return, you may filed an amended return using TurboTax Online to make the correction.  The 2019 Form 1040X for amending a tax return will not be available until 02/12/2020.  When available the  Amend (change) return link on the Tax Home web page will be active for 2019.

I filed my amended return in July 2020. I received my state amended taxes but have yet to receive my federal amended taxes. Should I resend my federal amended taxes in case it somehow got misplaced? Is there any software that I can buy to resend it or does it have to be mailed?

You can view these IRS publications for more information. 

Where's My Amended Return? Where's my amended return?

Form 1040X, Amended U.S. Individual Income Tax Return, Frequently Asked Questions

Frequently asked questions