and later in 1099-B form details, "Section 1256 Contracts - Regulated Futures and Nonequity Options", I do see transactio details, where capactured my transactions for "UVXY"
The information on your 1099-B for Section 1256 Contracts does not import into TurboTax. The "Summary Information" and supplemental information for your 1099-B is not actually part of the Tax Form. It needs to be reported and is provided to you, along with Form 1099-B so you can report it on your tax return. Your Section 1256 Contracts and Straddles are reported on Form 6781. To access Form 6781 in TurboTax (Desktop or Online) type "Form 6781" into Search. Next, click on "Jump to form 6781". This will take you to the screen with "Any Straddles or Section 1256 Contracts?" Answer Yes, and continue to complete Form 6781.
Before reporting you Section 1256 Contracts and Straddles, I recommend (as does the program) you review IRS Form 6781 Instructions. I also recommend you review IRS Publication 550 - Investment Income and Expenses for the special rules and elections that apply to Section 1256 Contracts and Straddles.
With online turbotax I typed Form 6781 in Search but there's no "Jump to form 6781", is that search the one on the top right that showing you related posts in the community, or there's another search?
I was trying to amend section 1256.
In the wages and income section of your federal return scroll down to "Investment Income'. The last entry there is 'Contracts and Straddles'. Click start or update next to that.