How can I edit IRA basis line 2 on form 8606?

You can change this line by entering your IRA basis information in TurboTax:

Search for IRA contributions using the search box located in the upper right corner .

1. Click on Jump to IRA contributions.
2. Check the box showing that you contributed to a Traditional IRA. 
3. The next screen asks you to verify that you contributed to a Traditional IRA, choose Yes.
4. The next screen asks if the contribution was a repayment of a retirement distribution, choose No.
5. Next, enter the amount that was contributed to the Traditional IRA. If didn't contribute for 2019, just enter 0.
6. The next screen is asking if you “recharacterized” the contribution.  This is different from a conversion, so the answer is No.
7. On the next screen, there will be a question about whether you are covered by a retirement plan at work.  Answer according to your situation. 
8. Following that, there will be a question about Excess IRA Contributions.  Answer this according to your situation.
9. The next question will be, Were there any nondeductible contributions to the IRA.  The answer here is Yes.
10. The next page asks for the basis of the Traditional IRA.  If you have never made nondeductible contributions in the past and kept them in the IRA, your basis is zero.  Otherwise, enter the amount shown as total basis on your most recently filed Form 8606.

Does this apply to desktops products as well? 

Yep ... if you use the Home & Business version then this is in the PERSONAL tab. 

It is also changeable in the 1099-R interview when you have a Traditional IRA distribution.  The interview will as for prior years basis.  If the carry-over amount is not correct, it can be changed by entering the correct amount that goes on the 8606 line 2, and an explanation statement.